Double-sided imprinting

ABSTRACT

Systems, apparatus, and methods for double-sided imprinting are provided. An example system includes first rollers for moving a first web including a first template having a first imprinting feature, second rollers for moving a second web including a second template having a second imprinting feature, dispensers for dispensing resist, a locating system for locating reference marks on the first and second webs for aligning the first and second templates, a light source for curing the resist, such that a cured first resist has a first imprinted feature corresponding to the first imprinting feature on one side of the substrate and a cured second resist has a second imprinted feature corresponding to the second imprinting feature on the other side of the substrate, and a moving system for feeding in the substrate between the first and second templates and unloading the double-imprinted substrate from the first and second webs.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a divisional of U.S. application Ser. No.15/990,155, filed May 25, 2018, which claims the benefit of the filingdate of U.S. Provisional Application No. 62/511,172, filed on May 25,2017. The contents of U.S. Application Nos. 62/511,172 and 15/990,155are incorporated herein by reference in their entirety.

TECHNICAL FIELD

This disclosure relates generally to imprinting technology, particularlyfor double-sided imprinting.

BACKGROUND

When developing a process and/or a tool for transitioning from creatingsingle sided imprints on a substrate to imprints on both sides fromtemplates, there are a lot of challenges to overcome. The challenges caninclude: positioning and aligning the substrate and the templates,locating reference features to assist in the alignment, creating theimprints without air entrapment and defects, and holding the substratewithout damage.

SUMMARY

The present disclosure describes methods, devices, and systems fordouble-sided imprinting, which have addressed the challenges mentionedabove.

One aspect of the present disclosure features a double-sided imprintingmethod including: drawing a first web along first rollers and drawing asecond web along second rollers, the first web comprising a firsttemplate and the second web comprising a second template; aligningreference marks on the first web and the second web, such that the firsttemplate and the second template are aligned with each other; drawingthe first web along the first rollers in a first direction to expose thefirst template to a first dispenser and drawing the second web along thesecond rollers in a second direction to expose the second template to asecond dispenser; dispensing first resist on the first template by thefirst dispenser and dispensing second resist on the second template bythe second dispenser; drawing the first web along the first rollers in adirection reverse to the first direction and drawing the second webalong the second rollers in a direction reverse to the second direction,such that the first template with the first resist and the secondtemplate with the second resist face to each other; inserting asubstrate between the first template with the first resist and thesecond template with the second resist; curing the first resist and thesecond resist, such that the cured first resist has a first imprintedfeature associated with the first template on a first side of thesubstrate and the cured second resist has a second imprinted featureassociated with the second template on a second side of the substrate;and unloading the substrate with the first imprinted feature on thefirst side and the second imprinted feature on the second side.

In some implementations, the method further includes: after thealigning, clamping the first web and the second web at a locationadjacent to the reference marks, such that the clamped first web andsecond web are moved with the first template and the second templatealigned with each other; and after the curing, unclamping the first weband the second web, such that the substrate with the cured first resistand second resist is capable of passing through a gap between the firstweb and the second web. Clamping the first web and the second web caninclude actuating a chuck with a clamp, such that the chuck is onto thefirst web and the clamp is onto the second web. The chuck can include avacuum chuck configured to chuck onto the first web with vacuum. In someexamples, the chuck is configured to be movable along a rail parallel toan axis defined by the first rollers, and the chuck and the clamp aremoved together with the first web and the second web after the clamping.The chuck can be positioned on a pair of guides, and each of the guidescan be movable on a respective rail connected to a frame. Aligningreference marks on the first web and the second web can includeadjusting relative positions of the guides on the respective rails in atleast one of x, y, or theta direction.

The first rollers and the second rollers can be arranged such that,after the inserting, the substrate is moved together with the firsttemplate and the second template, and the first resist is pressed ontothe first side of the substrate and filled into a first imprintingfeature on the first template and the second resist is pressed onto thesecond side of the substrate and filled into a second imprinting featureon the second template.

The method can further include: moving a first squeegee roller on thefirst web to push the first template into the first resist, such thatthe first resist fills into a first imprinting feature on the firsttemplate; and moving a second squeegee roller on the second web to pushthe second template into the second resist, such that the second resistfills into a second imprinting feature on the second template. The firstsqueegee roller and the second squeegee roller can be positionedopposite to each other during moving together the first squeegee and thesecond squeegee.

In some cases, aligning reference marks on the first web and the secondweb includes aligning a first reference mark on the first web with asecond reference mark on the second web and aligning a third referencemark on the first web with a fourth reference mark on the second web.The first reference mark and the third reference mark can define a rangewhere the substrate is configured to be imprinted with the firsttemplate. In some cases, aligning reference marks on the first web andthe second web includes moving a z-roller of the first rollers in atleast one of x, y, or theta direction. In some cases, aligning referencemarks on the first web and the second web includes locating thereference marks by using at least one of a camera system or a lasersystem.

The first direction can be counter-clockwise direction, and the seconddirection can be clockwise direction. In some examples, the firstrollers include at least one air turn roller configured to float thefirst web by air pressure. In some examples, the first rollers includeat least one air turn roller configured to chuck the first web byvacuum.

In some examples, the first rollers include two first z-rollers arrangedin a vertical direction, and the second rollers include two secondz-rollers arranged in the vertical direction. Dispensing first resist onthe first template by the first dispenser can include dispensing thefirst resist on the first template when the first template is in ahorizontal direction, and dispensing second resist on the secondtemplate by the second dispenser can include dispensing the secondresist on the second template when the second template is in thehorizontal direction.

In some examples, inserting the substrate includes inserting thesubstrate by a first holder along an inserting direction. In some cases,unloading the substrate includes moving the substrate with the first andsecond imprinted features along a direction reverse to the insertingdirection and unloading the substrate with the first and secondimprinted features by the first holder. In some cases, unloading thesubstrate includes moving the substrate with the first and secondimprinted features along the inserting direction and unloading thesubstrate with the first and second imprinted features by a second,different holder. The method can further include measuring first tensionof the first web by a first tension sensor and measuring second tensionof the second web by a second tension sensor. The method can furtherinclude controlling at least one of temperature or cleanness of achamber enclosing at least the first template and the second template.

The method can include: before drawing the first template into animprinting region and when the first web is static, locating a firstreference mark on the first web using a detecting system positionedupstream one of the first rollers. The method can include: locating afirst reference mark on the first web with a reference mark on thesubstrate; aligning the first reference mark on the first web with thereference mark on the substrate; and after the alignment, clamping thefirst reference mark to move the first web such that the first templateis moved to an imprinting start position in synchronization with animprinting start position of the substrate. The method can furtherinclude: aligning reference marks on the first web and the second webincludes: measuring an angle of the first web by one or more sensorsarranged on an edge of the first web; and repositioning the substratebased on the measured angle of the first web.

Another aspect of the present disclosure features a system fordouble-sided imprinting, including: first rollers for moving a first webincluding a first template; second rollers for moving a second webincluding a second template; an alignment system configured to alignreference marks on the first web and the second web such that the firsttemplate and the second template are aligned with each other; a firstdispenser configured to dispense first resist on the first template; asecond dispenser configured to dispense second resist on the secondtemplate; a loading system configured to insert a substrate between thefirst template and the second template; and a light source configured tocure the first resist and the second resist, such that the cured firstresist has a first imprinted feature associated with the first templateon a first side of the substrate and the cured second resist has asecond imprinted feature associated with the second template on a secondside of the substrate. In operation, the first web is drawn along thefirst rollers in a first direction to expose the first template to thefirst dispenser and the second web is drawn along the second rollers ina second direction to expose the second template to the seconddispenser, and then, the first web is drawn along the first rollers in adirection reverse to the first direction and the second web is drawnalong the second rollers in a direction reverse to the second direction,such that the first template with the first resist and the secondtemplate with the second resist face to each other.

In some implementations, the system further includes an unloading systemconfigured to unload the substrate with the first imprinted feature onthe first side and the second imprinted feature on the second side. Insome cases, the loading system is configured to unload the substratewhen the substrate with the first and second imprinted feature isreversely moved back to the loading system.

In some implementations, the system further includes a clamping systemconfigured to: clamp the first web and the second web at a locationadjacent to the reference marks, such that the clamped first web andsecond web are moved with the first template and the second templatealigned with each other; and unclamp the first web and the second web,such that the substrate with the cured first resist and second resist iscapable of passing through a gap between the first web and the secondweb. The clamping system can include: a chuck configured to chuck thefirst web; and a clamp configured to clamp the second web when actuatedwith the chuck. The chuck can include a vacuum chuck configured to chuckonto the first web with vacuum. The chuck can be configured to bemovable along a rail parallel to an axis defined by the first rollers,and the chuck and the clamp can be moved together with the first web andthe second web after clamping the first web and the second web. In someexamples, the chuck is positioned on a pair of guides, and each of theguides is movable on a respective rail connected to a frame, and thealignment system is configured to align the reference marks on the firstweb and the second web by adjusting a relative position of the guides onthe respective rails in at least one of x, y, or theta direction.

The first rollers and the second rollers can be arranged such that thesubstrate is moved together with the first template and the secondtemplate, and the first resist is pressed onto the first side of thesubstrate and filled into a first imprinting feature on the firsttemplate and the second resist is pressed onto the second side of thesubstrate and filled into a second imprinting feature on the secondtemplate. The alignment system can be configured to align the referencemarks on the first web and the second web by moving a z-roller of thefirst rollers in at least one of x, y, or theta direction. The systemcan further include a locating system configured to locate the referencemarks on the first web and the second web for alignment, and thelocating system can include at least one of a camera system or a lasersystem.

The first direction can be counter-clockwise direction, and the seconddirection can be clockwise direction. In some examples, the firstrollers include at least one air turn roller configured to float thefirst web by air pressure. In some examples, the first rollers includeat least one air turn roller configured to chuck the first web byvacuum. In some examples, the first rollers include two first z-rollersarranged in a vertical direction, and the second rollers include twosecond z-rollers arranged in the vertical direction, and the firstdispenser can be configured to dispense the first resist on the firsttemplate when the first template is in a horizontal direction, and thesecond dispenser is configured to dispense the second resist on thesecond template when the second template is in the horizontal direction.

The system can further include first and second tension sensorsconfigured to measure tension of the first web and the second web,respectively. The system can further include a chamber configured toenclose the first template and the second template and a controllerconfigured to control at least one of temperature or cleanness of thechamber.

A third aspect of the present disclosure features a double-sidedimprinting method including: drawing a first web along first rollers,the first web comprising a first template having a first imprintingfeature; dispensing first resist on the first template; loading asubstrate onto the first template, such that a first side of thesubstrate is in contact with the first resist on the first template;clamping the substrate onto the first template, such that the substrateis movable together with the first template; dispensing second resist ona second side of the substrate; aligning a first reference mark on thefirst web with a second reference mark on a second web that includes asecond template having a second imprinting feature, such that the secondimprinting feature is aligned with the first imprinting feature; afterthe aligning, drawing the first web along the first rollers and drawingthe second web along second rollers simultaneously at a same rate;curing the first resist and the second resist, such that the cured firstresist has a first imprinted feature corresponding to the firstimprinting feature on the first side of the substrate and the curedsecond resist has a second imprinted feature corresponding to the secondimprinting feature on the second side of the substrate; and unloadingthe substrate with the first imprinted feature on the first side and thesecond imprinted feature on the second side.

The method can further include waiting until the first resist spreadsinto the first imprinting feature of the first template. The firstimprinting feature can include a grating feature, and the gratingfeature can be configured such that the first resist uniformly fillsinto the grating feature.

The first reference mark can be positioned ahead of the first imprintingfeature on the first web along a direction of drawing the first web, andthe second reference mark can be positioned ahead of the secondimprinting feature on the second web along the direction. In someexamples, the first template includes one or more pre-pattered throughholes, and clamping the substrate onto the first web includes holdingwith vacuum the substrate by a vacuum chuck through the one or morepre-patterned through holes.

In some implementations, the first rollers include two first z-rollersarranged in a horizontal direction, and the second rollers include twosecond z-rollers arranged in the horizontal direction. The two firstz-rollers can define a first moving range for the first web and the twosecond z-rollers can define a second moving range for the second web,and the first moving range can be larger than the second moving rangeand can enclose the second moving range. In some cases, the firstrollers and the second rollers are arranged to define a verticaldistance between the first template and the second template, and thevertical distance can be defined such that the second resist is pressedonto the second side of the substrate and filled into the secondimprinting feature on the second template.

The method can further include: before the curing, moving a squeegeeroller onto the second web to push the second template into the secondresist, such that the second resist fills into the second imprintingfeature. The method can further include: after the aligning, moving thesecond rollers together with the second web to be in contact with thesecond resist on the second side of the substrate, such that the secondtemplate is pressed into the second resist and the second resist fillsinto the second imprinting feature.

In some examples, unloading the substrate includes: pulling the secondweb away from one of the second rollers to separate from the substrate;and unclamping the substrate and taking from the first web thesubstrate.

A fourth aspect of the present disclosure features a system fordouble-sided imprinting, including: first rollers for moving a first webincluding a first template having a first imprinting feature; secondrollers for moving a second web including a second template having asecond imprinting feature; a first dispenser configured to dispensefirst resist on the first template; a loading system configured to loada substrate onto the first template, such that a first side of thesubstrate is in contact with the first resist on the first template; aclamping system configured to clamp the substrate onto the first web,such that the substrate is movable together with the first web; a seconddispenser configured to dispense second resist on a second side of thesubstrate; a locating system configured to locate a first reference markon the first web with a second reference mark on the second web foraligning the first reference mark with the second reference mark; alight source configured to cure the first resist and the second resist,such that the cured first resist has a first imprinted featurecorresponding to the first imprinting feature on the first side of thesubstrate and the cured second resist has a second imprinted featurecorresponding to the second imprinting feature on the second side of thesubstrate; and an unloading system configured to unload the substratewith the first imprinted feature on the first side and the secondimprinted feature on the second side. After the first reference mark andthe second reference mark are aligned with each other, the first web andthe second web are drawn simultaneously at a same rate.

The first imprinting feature of the first template can include a gratingfeature, and the grating feature can be configured such that the firstresist uniformly fills into the grating feature. The first referencemark can be positioned ahead of the first imprinting feature on thefirst web along a direction of drawing the first web, and the secondreference mark is positioned ahead of the second imprinting feature onthe second web along the direction. The first template can include oneor more pre-pattered through holes, and the clamping system comprises avacuum chuck configured to hold with vacuum the substrate through theone or more pre-patterned through holes.

In some implementations, the first rollers include two first z-rollersarranged in a horizontal direction, and the second rollers include twosecond z-rollers arranged in the horizontal direction. The two firstz-rollers can define a first moving range for the first web and the twosecond z-rollers can define a second moving range for the second web,the first moving range being larger than the second moving range andenclosing the second moving range. The first rollers and the secondrollers can be arranged to define a vertical distance between the firsttemplate and the second template, and the vertical distance can bedefined such that the second resist is pressed onto the second side ofthe substrate and filled into the second imprinting feature on thesecond template.

The first dispenser, the loading system, the second dispenser, thelocating system, the light source, and the unloading system can bearranged sequentially along a direction of drawing the first web alongthe first rollers. The system can further include a squeegee rollerconfigured to apply pressure onto the second web to push the secondtemplate into the second resist, such that the second resist fills intothe second imprinting feature of the second template.

The first rollers can include at least one air turn roller configured tofloat the first web by air pressure. The second rollers can beconfigured to be movable together with the second web to be in contactwith the second resist on the second side of the substrate after thealigning, such that the second template is pressed into the secondresist and the second resist fills into the second imprinting feature.In some examples, the loading system can include an equipment front endmodule (EFEM), and the unloading system can include a second EFEM. Insome examples, the locating system includes at least one of a camerasystem or a laser system. The system can further an alignment systemconfigured to align the first reference mark on the first web with thesecond reference mark on the second web.

A fifth aspect of the present disclosure features a double-sidedimprinting method including: drawing a first web along first rollers anddrawing a second web along second rollers until a first template of thefirst web and a second template of the second web are brought togetherinto an imprinting zone; aligning reference marks for the first templateand the second template; dispensing first resist on a first side of asubstrate and a second resist on a second side of the substrate; feedingthe substrate into the imprinting zone between the first template andthe second template; pressing the first template and the second templateonto the substrate, such that the first resist fills into a firstimprinting feature of the first template on the first side of thesubstrate and the second resist fills into a second imprinting featureof the second template on the second side of the substrate; curing thefirst resist and the second resist, such that the cured first resist hasa first imprinted feature corresponding to the first imprinting featureon the first side of the substrate and the cured second resist has asecond imprinted feature corresponding to the second imprinting featureon the second side of the substrate; and unloading the substrate withthe first imprinted feature on the first side and the imprinted featureon the second side.

In some cases, pressing the first template and the second template ontothe substrate can include applying a first press dome on the firsttemplate. In some cases, pressing the first template and the secondtemplate onto the substrate can include applying a second press dome onthe second template.

In some implementations, pressing the first template and the secondtemplate onto the substrate includes: moving a first squeegee rolleronto the first web to push the first template into the first resist,such that the first resist fills into the first imprinting feature onthe first template; and moving a second squeegee roller onto the secondweb to push the second template into the second resist, such that thesecond resist fills into the second imprinting feature on the secondtemplate. The first squeegee roller and the second squeegee roller canbe positioned opposite to each other during moving the first squeegeeand the second squeegee together.

The method can further include: bringing the first press dome intocontact with the first template and bringing the second press dome intocontact with the second template; and making a correction for alignmentof the first template and the second template. The second press dome caninclude a glass dome or an annular ring vacuum chuck. The first pressdome can include a glass dome or an annular ring vacuum chuck. Unloadingthe substrate can include: pulling the first web away from one of thefirst rollers and pulling the second web away from one of the secondrollers to separate the first template and the second template from thesubstrate.

In some cases, the substrate is rigid, and feeding the substrateincludes presenting the substrate by gripping an edge of the substrateusing a holder. In some cases, the substrate is flexible, and feedingthe substrate includes drawing the substrate from a roll of blanksubstrates. The method can further include: after the substrate isseparated from the first template, applying a first protective film ontothe cured first resist on the first side of the substrate; and after thesubstrate is separated from the second template, applying a secondprotective film onto the cured second resist on the second side of thesubstrate. The method can further include rolling the substrate with thecured first resist on the first side and the cured second resist on thesecond side over a roller.

A sixth aspect of the present disclosure features a double-sidedimprinting method including: drawing a first web along a first rollerand a second roller, the first web comprising a first template having afirst imprinting feature; drawing a second web along a third roller anda fourth roller, the second web comprising a second template having asecond imprinting feature, the first roller and the third roller beingpositioned opposite to each other and defining a nip; aligning referencemarks for the first template and the second template; dispensing firstresist on one of a first side of the substrate and the first template;dispensing second resist on one of a second side of the substrate andthe second template; simultaneously drawing the first template and thesecond template into the nip and feeding the substrate into the nip withthe first imprinting feature facing the first side of the substrate andthe second imprinting feature facing the second side of the substrate,such that the first resist is pressed by the first roller into the firstimprinting feature on the first side of the substrate and the secondresist is pressed by the third roller into the second imprinting featureon the second side of the substrate; curing the first resist and thesecond resist, such that the cured first resist has a first imprintedfeature corresponding to the first imprinting feature on the first sideof the substrate and the cured second resist has a second imprintedfeature corresponding to the second imprinting feature on the secondside of the substrate; and unloading the substrate with the firstimprinted feature on the first side and the second imprinted feature onthe second side.

In some cases, unloading the substrate includes pulling the first webaway from the second roller and the second web away from the fourthroller to separate the first template and the second template from thesubstrate. In some cases, unloading the substrate includes reverselydrawing the first web from the first roller and the second web from thethird roller and retracting the substrate to separate the first templateand the second template from the substrate.

A seventh aspect of the present disclosure features a system fordouble-sided imprinting, including: first rollers configured to move afirst web including a first template having a first imprinting feature;second rollers configured to move a second web including a secondtemplate having a second imprinting feature; one or more dispensersconfigured to dispense resist; a locating system configured to locatereference marks on the first web and the second web for aligning thefirst template and the second template; a light source configured tocure the resist, such that a cured first resist has a first imprintedfeature corresponding to the first imprinting feature on a first side ofthe substrate and a cured second resist has a second imprinted featurecorresponding to the second imprinting feature on a second side of thesubstrate; and a moving system configured to feed in the substratebetween the first template and the second template and unload thesubstrate with the first imprinted feature on the first side and thesecond imprinted feature on the second side. The dispensers can beconfigured to dispense the first resist on one of the first side of asubstrate and the first template and the second resist on one of thesecond side of the substrate and the second template.

In some implementations, one of the first rollers and one of the secondrollers are positioned opposite to each other and define a nip, and themoving system is configured to feed the substrate into the nip when thefirst template and the second template are drawn into the nip with thefirst imprinting feature facing the first side of the substrate and thesecond imprinting feature facing the second side of the substrate, suchthat the first resist is pressed by the first roller into the firstimprinting feature on the first side of the substrate and the secondresist is pressed by the third roller into the second imprinting featureon the second side of the substrate.

In some cases, the first web is pulled away from another one of thefirst rollers and the second web is pulled away from another one of thesecond rollers that is positioned opposite to the one of the firstrollers, such that the substrate is separated from the first templateand the second template. In some cases, the moving system is configuredto retract the substrate to separate from the first template and thesecond template when the subs first web and the second web are reverselydrawn away from the one of the first rollers and the one of the secondrollers, respectively.

In some implementations, the system further includes a pressing systemconfigured to press the first template and the second template onto thesubstrate, such that the first resist fills into the first imprintingfeature of the first template on the first side of the substrate and thesecond resist fills into the second imprinting feature of the secondtemplate on the second side of the substrate.

In some examples, the pressing system includes a first press domeconfigured to be applied on the first template. The first press dome caninclude a glass dome or an annular ring vacuum chuck. In some examples,the pressing system includes a second press dome configured to beapplied on the second template. The second press dome can include aglass dome or an annular ring vacuum chuck. The system can furtherinclude a correction system configured to make a correction foralignment of the first template and the second template when the firstpress dome is pressed onto contact with the first template and thesecond press dome is pressed onto contact with the second template.

In some implementations, the system includes a first squeegee rollerconfigured to be moved onto the first web to push the first templateinto the first resist, such that the first resist fills into the firstimprinting feature on the first template; and a second squeegee rollerconfigured to be moved onto the second web to push the second templateinto the second resist, such that the second resist fills into thesecond imprinting feature on the second template. The first squeegeeroller and the second squeegee roller can be positioned opposite to eachother during moving the first squeegee and the second squeegee together.

In some cases, the moving system includes a holder configured to grip anedge of the substrate. In some cases, the system includes a roller ofblank substrates, and the moving system is configured to rotate theroller to feed the substrate.

In some implementations, the system further includes a first roller offirst protective film configured to be applied onto the cured firstresist on the first side of the substrate and a second roller of secondprotective film configured to be applied on the cured second resist onthe second side of the substrate. The system can further include aroller configured to be rotated to receive the substrate with the curedfirst resist on the first side and the cured second resist on the secondside.

The details of one or more disclosed implementations are set forth inthe accompanying drawings and the description below. Other features,aspects, and advantages will become apparent from the description, thedrawings and the claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a schematic diagram of an example imprinting tool with adirect annular template chucking with a web dome.

FIG. 2 shows a schematic diagram of an example imprinting tool with anindirect template chucking with a glass dome.

FIG. 3A shows a schematic diagram of an example template vacuumchucking.

FIG. 3B shows a schematic diagram of an example air/vacuum bar chucking.

FIG. 4A shows a schematic diagram of example alternating regions ofpressure and vacuum.

FIG. 4B shows a schematic diagram of an example of glass dome templatebacking plate with substrate pressure dome.

FIGS. 5A-5B show schematic diagrams of examples of locating referencemarks on templates.

FIGS. 5C-5D show schematic diagrams of examples of locating referencemarks on substrates.

FIGS. 5E-5F show schematic diagrams of examples of locating referencemarks on templates.

FIGS. 5G-5H show schematic diagrams of an example of side-to-sideimprinting alignment with a vacuum chuck.

FIG. 6A shows a schematic diagram of an example of using a squeegeeroller during imprinting.

FIG. 6B shows a schematic diagram of another example of using a squeegeeroller during imprinting.

FIG. 7A shows a schematic diagram of an example of implementing a thetaadjustment method.

FIG. 7B shows a schematic diagram of an example of implementing a webangle measurement method.

FIG. 8 shows a schematic diagram of an example system of making adouble-sided imprint on a substrate.

FIG. 9 shows a schematic diagram of another example system of formingimprint on both sides of a substrate at once.

FIG. 10 shows a schematic diagram of an example system of usinglow-cost, flexible substrates in a roll format with double glass domeimprinting.

FIG. 11A shows a schematic diagram of an example tool for double-sidedimprinting.

FIG. 11B shows a schematic diagram of another example tool fordouble-sided imprinting.

FIGS. 12A-1 to 12I show schematic diagrams of example procedures ofusing the tool of FIG. 11A for double-sided imprinting.

FIGS. 13A-13F show schematic diagrams of example feature configurationsof the tool of FIG. 11A for double-sided imprinting.

FIG. 14 shows a schematic diagram of another example tool fordouble-sided imprinting.

FIGS. 15A to 15H show schematic diagrams of example procedures of usingthe tool of FIG. 14 for double-sided imprinting.

FIG. 16 is a flow diagram of an example process of fabricatingdouble-sided imprints on a substrate.

FIG. 17 is a flow diagram of another example process of fabricatingdouble-sided imprints on a substrate.

FIG. 18 is a flow diagram of a third example process of fabricatingdouble-sided imprints on a substrate.

FIG. 19 is a flow diagram of a fourth example process of fabricatingdouble-sided imprints on a substrate.

DETAILED DESCRIPTION

For double-sided imprinting, a positional alignment of an imprintedfeature from one side to another side is of critical importance inmanufacture of some devices. In some implementations, the alignment of atop side template to a pattern on the bottom side of the substraterequires finding reference marks on both the template and the substrateand then uses a high resolution positioning system to register thetemplate and substrate with respect to each other. After the alignment,the template can be carefully pressed against the substrate as not tocreate pockets of entrapped air and ensure the detail features of thetemplate is completely filled. Once an illumination light, e.g.,ultraviolet (UV) light, cures a resist, e.g., a UV curable resist,between the template and substrate, the template can be separated andthe pattern can stand on both sides of the substrate.

The imprinting process involves bringing the substrate with UV curableresist in contact with the template web as the template web is movingunderneath a roller. The rolling action can cause the UV resist to fillthe spaces in the template and push out all the air. At this point theUV resist is cured, and the template is separated from the substrateunderneath a roller as the web path turns and moves away from the linearmotion of the substrate on the vacuum chuck.

As the template is carried by a flexible, moving web, it is difficult todetermine the template's position with a high degree of accuracy. Theweb is able to move side to side by small amounts as the web advancesover the rollers in the tool. The web can be advanced by rollersconnected to motors. These rollers have variations in diameters and therotary encoders have limited resolutions. The web is also flexible, sotension variations cause the web and template to stretch as well as movein the vertical direction.

In some implementations, the web is advanced into a zone where thetemplate is available for imprinting on the substrate and a camerasystem is used to locate registration marks on the template. Once thepositions of the reference marks are found, the template can be used tocreate the imprint on the substrate without moving the web. In this way,the move after locating the substrate can be eliminated, which ensures agreater positional accuracy of the template and better alignment to theimprint on the opposite side of the substrate. In some implementations,imprint features are transferred to a substrate without relying onadvancement of a web over a leading roller.

The present disclosure describes methods, devices, and systems fordouble-sided imprinting, which have addressed the challenges mentionedabove. FIGS. 1 to 4B show example template chucking methods. FIGS. 5A to5H show examples of locating reference marks on templates and substratesfor side-to-side imprint alignment. FIGS. 6A-6B show example squeegeerollers for pushing a template into a resist along a substrate duringimprinting. FIGS. 7A-7B shows examples of theta adjustment forcorrecting angular misalignment of rollers and wed angle measurement.FIGS. 8-10 show example implementations of double-sided imprinting.FIGS. 11A to 13F show example tools for aligned-double-sided imprintswith associated procedures and configurations. FIGS. 14 to 15H show anexample tool for simultaneous double-sided imprints with associatedprocedures. FIGS. 16 to 19 show example processes of fabricatingdouble-sided imprints on a substrate, e.g., using the devices, systems,or tools described above.

These technologies described in the present disclosure can be applied tofabricating any suitable micro or nanostructures or any double sidepatterning structures, e.g., diffraction gratings on single side or bothsides of any suitable substrates (e.g., rigid or flexible materials). Inone example, the technologies can be utilized to fabricate a diffractiveoptical element (DOE) for an eyepiece as described in a U.S. patentapplication Ser. No. 14/726,424, entitled “Methods and systems forgenerating virtual content display with a virtual or augmented realityapparatus” and filed on May 29, 2015 herewith, whose content is herebyincorporated by reference in its entirety. The DOE can have one or morelayers, and each layer can include an orthogonal pupil expansion (OPE)diffractive element and an exit pupil expansion (EPE) diffractiveelement. In some cases, the OPE diffractive element and the EPEdiffractive element can be fabricated on opposite sides of a waveguidesubstrate. In some cases, the OPE diffractive element and the EPEdiffractive element can be fabricated on one side of a waveguidesubstrate and other components can be fabricated on the other side ofthe waveguide substrate. In another example, the technologies can beutilized to fabricate a diffraction grating on one side of a substratewith a varying structure on the other side of the substrate, asdescribed in FIG. 7E of a U.S. provisional patent application62/447,608, entitled “Manipulating optical phase variations indiffractive structures” and filed on Jan. 18, 2017 herewith, whosecontent is hereby incorporated by reference in its entirety.

Examples Template Chucking Methods

I. Direct Annular Template Chucking with Web Dome

As a template is carried by a flexible, moving web, it is difficult todetermine a position of the template with a high degree of accuracy. Theflexible template (e.g., coated resist template—CRT) is able to moveside to side by small amounts as the web advances over rollers in animprinting tool. When the template is advanced by the rollers connectedto motors, motion error accumulates since these rollers have variationsin their diameters and rotary encoders have limited resolutions. The webis also flexible, so tension variations cause the web and the templateto stretch as well as move in a vertical direction. In someimplementations, an annular ring grabs the template with vacuum, andthus the web is able to be moved with a set of precision stages to alignit to a reference mark on the substrate while the web is being guidedthrough an optical feedback up to a point of contact.

FIG. 1 shows an example imprinting tool 100 with a direct annulartemplate chucking with a web dome. A web 102 is drawn against an annularring vacuum chuck 104 that is located above the web 102 and betweenz-rollers 106 a, 106 b in the imprinting tool 100. The ring vacuum chuck104 has a cavity 108 inside the vacuum region that can be covered andsealed with a glass window 110. The glass window 110 allows for a visionsystem 112 to accurately locate reference marks on a template 120 on theweb 102, a UV curing light 114 to harden a UV resist 116, and pressureor vacuum to be applied to the web 102 in the region inside the ringvacuum chuck 104.

When pressure is applied to the region inside the annular ring vacuumchuck 104, the web 102 with the template 120 can bow outward like aballoon with the area in the center of the ring pushed down slightlytoward a substrate 118 on a stage 130 that can be moved vertically(e.g., along Z direction) and horizontally (e.g., along X direction). Asthe template 120 and the substrate 118 come together for imprinting(either by moving the template 120 down or the substrate 118 up) thecenter portion of the template 120 can touch the substrate 118 first ina small circular area, and as the template 120 and the substrate 118 arebrought closer, the contact area will continue to increase as air ispushed out of the way and the resist fills in details within thetemplate 120. At this point, the resist 116 is hardened by light 114,the ring vacuum chuck 104 releases the template 120, and the stage 130and the web 102 are advanced together until separation occurs at thez-roller 106 a or 106 b.

Holding of a flexible template, e.g., the template 120, with an annularring vacuum chuck, e.g., the ring vacuum chuck 104, provides severaladvantages. First, this technique secures the template for accuratepositioning. Second, if the template is a clear, material, the techniqueallows for a vision system to see through to alignment marks on thesubstrate below and perform a precision alignment. This technique alsoallows pressure to be applied to the back of the template to bow thetemplate so when contact is made with the substrate, the touch point canbe at the center and air can be forced out between the template and thesubstrate. The clear template allows for a UV cure step to harden thefeatures. For separation of the template from the features, the vacuumis released and the web with the substrate are driven forward andseparation occurs at a roller as the path of the web leaves the linearpath of the substrate.

II. Indirect Template Chucking with Glass Dome

FIG. 2 shows an example imprinting tool 200 with an indirect templatechucking with a glass dome. Imprinting forces can be applied with aseparate pressurized dome assembly 204 that can be lowered into abackside of a web 202 above a template 220. The glass dome 204 caninclude a thin piece of transparent glass 210 that takes a dome shapewhen a closed volume 208 behind the glass 210 is pressurized. The glassback surface allows for optical template reference mark location by avision system 212 and UV curing by a UV light 214. Once the dome shapedglass 204 is lowered into the back of the web 202, the friction betweenthem can lock the web 202 in place. At this point, the vision system212, e.g., cameras, can find reference marks on the template 220 and ona substrate 218 below. A stage assembly 230 that holds the substrate canmove the reference marks into alignment with an optical feedback, e.g.,horizontally along X direction.

After the alignment, the substrate 218 is brought out from under thetemplate 220 and UV curable resist 216 is applied, then the substrate218 is brought back to the aligned position for the imprinting. As thedome 204 and the template 220 are moved, e.g., vertically, into thesubstrate 218, the template 220 will first contact the substrate 218 inthe center and the contact patch will grow outward, pushing air out ofthe way. At this point, the imprint can be cured with UV, then the dome204 can be raised and separated from the backside of the flexibletemplate 220. The web 202 can be advanced together with the substrate218 on the vacuum chuck 204 and the template 220 can separate from thesubstrate 218 at z-rollers 206 a or 206 b.

III. Template Vacuum Chucking & Air/Vacuum Bar Chucking

FIG. 3A shows a schematic diagram of an example template vacuum chucking300. A web 302 is drawn along two z-rollers 306 a, 306 b. The web 302can be chucked with vacuum by vacuum chucks 308, 310 in certainlocations around a template region including a template 320 to preventthe web 302 from slipping around the z-rollers 306 a, 306 b or to keeptension variations from inducing errors in a position of the web 302. Asillustrated in FIG. 3A, the two vacuum chucks 308, 310 can be arrangedbefore and after the high friction z-roller 306 b respectively. Thevacuum chuck 308 is adjacent but away from the template 320. The web 302can be stopped by locking the high friction z-roller 306 a and/or 306 bwith brakes 304 and maintaining tension with drive motors upstream anddownstream of an imprinting zone. A vision system 312 can directlylocate reference marks on the template 320 on the web 302. A UV curinglight 314 can also directly harden a UV resist on the template 320.

FIG. 3B shows a schematic diagram of an example air/vacuum bar chucking350. An air bearing turn bar 354 is used in FIG. 3B in place of aleading z-roller, e.g., the z-roller 406 b in FIG. 3A. A web 352 isdrawn along the air bearing turn bar 354 and a z-roller 356. In somecases, the air bearing turn bar 354 can have its air pressure switch tovacuum and can act to clamp the web 352 after the web 352 is stopped ina region where template reference marks for a template 370 can beaccurately located. As discussed in FIG. 13B with further details, theair bearing turn bar 354 can float the web 352 and do not put anylateral or angular constraint on the web 352.

IV. Glass Dome Template Backing Plate with Substrate Pressure Dome

A critical technical challenge to imprint on both sides of a substrateby imprinting one side at a time is the holding of the substrate for theimprint without damaging the patterns on the backside. If a pattern onthe backside comes into contact with the vacuum chuck or wafer handlingend effector, damage can occur from three or more modes: a first damagemode could be a scratch of the imprinted pattern; a second damage modecould happen if any debris falls on the vacuum chuck that is transferredto the substrate; a third damage mode can be for the vacuum chuck to becontaminated with uncured resist that somehow gets transferred to thesubstrate and cured as a defect. In some cases, a double sided processwhere the substrate is gripped by a robot along the edge can eliminatemost of these defect issues, but the robot can add complication.

In some implementations, a vacuum chuck is created with pockets torelieve areas for the imprinted patterns. This can help relieve theissue of scratching and may not prevent other defect modes.

FIG. 4A shows a schematic diagram of example alternating regions 400 ofpressure and vacuum. As illustrated, a substrate 402 is held with vacuumby a vacuum chuck in two small regions 404 a, 404 b around a perimeterof the substrate 402. Area 406 for imprinting is surrounded by theperimeter and in the center of the substrate 402. Optical referencemarks 408 are around the perimeter and outside of the area 406. Thesubstrate 402 has a tight array of vacuum and pressure zones 410 so asto minimize distortion of the substrate 402 while keeping the substrate402 from touching the vacuum chuck. This wafer chucking can eliminatescratching and particle contamination. In some cases, this waferchucking has local elastic distortions while chucking under the pressureand vacuum regions. The amplitude of the distortions can be exacerbatedby a reduction in substrate thickness. However, these distorted areasmay be flattened out during the imprinting process.

FIG. 4B shows a schematic diagram of an example 450 of glass dometemplate backing plate with substrate pressure dome. A web 452 is drawnalong two z-rollers 456 a, 456 b that can be moved up and downvertically. A substrate 458 that is matched in mechanical bendingproperties of the glass dome 454 can be held by a vacuum chuck 460 on astage 480 in an annular vacuum region along an edge. The center of thevacuum chuck 460 can have deep recess so as not to touch any criticalfeatures or transfer any debris. After alignment of the substrate 458and the template 470, the glass dome 454 can push downward pressing thetemplate 470 into the substrate 458, first making small circular contactin the center and growing to the edges of the substrate 458 as a fullcontact is achieved. Curing and separation can occur and the web 452 canbe peeled off the substrate 458 in a typical manner around the z-roller456 a.

Examples of Locating Reference Marks and Imprinting Alignment

Another critical technical challenge of imprinting on both sides of asubstrate is to accurately locate a reference mark on a template and areference mark on a back side of the substrate.

FIGS. 5A-5B show schematic diagrams of examples 500, 530 of locatingreference marks on templates. A web 502 is drawn along two z-rollers 506a, 506 b. As FIG. 5A shows, a reference mark 512, e.g., a diffractionpattern, on a template 510 is located with a laser light from a laser504 from an opposite side of the web 502 when a protection layer isremoved. A laser sensor 508 is positioned on a movable stage 520 andconfigured to detect the laser light 504 through the web 502. If thereference mark 512 on the template 510 is moved between the laser 504and the laser sensor 508, the laser light is diffracted or blocked bythe reference mark 512, and consequently an intensity of the laser lightdetected by the laser sensor 508 will be changed. Based on the change ofthe detected laser light intensity, a location of the reference mark 512can be determined.

In some cases, as FIG. 5B shows, the laser 504 can also be used todetect a reference mark 514 on an edge of the template 510 when thetemplate 510 is mounted to an edge of a vacuum chuck and looked up. Thevacuum chuck can be an x-stage air-bearing vacuum chuck, e.g., theair/vacuum bar vacuum chuck 354 of FIG. 3B. A camera system can also beused to locate the reference mark 512 or 514 from the top of thetemplate 510 or mounted facing the vacuum chuck.

FIGS. 5C-5D show schematic diagrams of examples 550, 570 of locatingreference marks on substrates. A separate laser 554 (FIG. 5C) or acamera system 572 (FIG. 5D) can find a reference mark 562 on a substrate560 after the substrate 560 is acquired, e.g., by a vacuum chuck stage.This camera system 572 or the laser 554 can be pointed downward andfixed to check the substrate 560. The substrate 560 can be moved in xand y by the vacuum chuck stage to find a center of the reference mark562.

If a camera system is used to look down at a reference mark 512 or 514on the template 510, and a downward looking camera 572 is used to findthe reference mark 562 on the substrate 560, it may be possible to placeseparate reference target on the vacuum chuck stage that is visible andmeasurable by both the cameras. Knowing a position of the x-y stage ofthis reference marks in both cameras can enable a simple way toinitially align both vision systems.

FIGS. 5E-5F show schematic diagrams of examples 580, 585 of locatingreference marks on templates. Before the template 510 is moved forimprinting, the template 510 is positioned before the z-roller 506 bwith an angle relative to a horizontal direction. A laser 582 (FIG. 5E)or a camera system 586 (FIG. 5F) can be arranged before (or upstream)the z-roller 506 b and aligned with the template 510 with a similarangle relative to the horizontal direction. A first-side imprint can beformed on a first side of the substrate 560, e.g., by aligning with areference mark on the substrate 560. The angled laser 582 or the angledcamera system 586 can locate a fiducial reference mark 512 on thetemplate 510 when the web 502 does not need to move and before asecond-side imprint to be formed on a second, opposite side of thesubstrate 560 starts. The fiducial reference mark 512 can be alignedwith the reference mark 562 on the substrate 560 for the second-sideimprint, e.g., using the laser 554 or the camera system 572 shown inFIGS. 5C and 5D. In this way, an imprecise template move of the flexibletemplate 510, e.g., CRT, can be eliminated to thereby increase thealignment accuracy (overlay) of the second-side imprint relative to thefirst-side imprint formed on the first side of the substrate 560.

FIGS. 5G-5H show schematic diagrams of an example 590 of side-to-sideimprinting alignment with vacuum chuck. A first imprint template 510 aon a first web 502 a can be under tension to remove sag, then a set ofcameras, e.g., including a camera 592, can be used to locate a firstfiducial mark 512 a on the first imprint template 510 a, optionally asecond fiducial mark 512 b on a second imprint template 510 b of asecond web 502 b, and a fiducial mark 562 on a side of a substrate 560in the same view. A stage holding the substrate 560 can bring thefiducial marks 512 a, 512 b and 562 into alignment. After the alignment,a vacuum chuck 594 above the first web 502 a can grab the first imprinttemplate 510 a from above, as illustrated in FIG. 5G. The vacuum chuck594 can be connected to a precision moving mechanism that can move thefirst imprint template 510 a to an imprint-start position that is insynchronization with an imprint-start position of the substrate 560, asillustrated in FIG. 5H. This can eliminate an imprecise movement of thefirst imprint template 510 a and allow for side-to-side imprintalignment, e.g., a first imprint to be formed from the first imprinttemplate 510 a on a first side of the substrate 560 to be aligned with asecond imprint to be formed from the second imprinted template 510 b ona second, opposite side of the substrate 560.

Example Squeegee Rollers

FIG. 6A shows a schematic diagram of an example 600 of using a squeegeeroller during imprinting. A web 602 is drawn along two z-rollers 606 a,606 b. After the web 602 is stopped and reference marks of a template610 and a substrate 616 (not shown) by a vision system 612 are located,an additional roller 608 (called a squeegee roller) is configured to belowered, e.g., along Z direction, into a back of the web 602 and pushthe template 610 into a resist 618 along the substrate 616 on a stage620. The squeegee roller 608 can be able to traverse between thez-rollers 606 a, 606 b forcing out air as the roller 608 moves back andforth along X direction and can help to fill details of the template610. The squeegee roller 608 can move out of the way, the resist 618 canbe cured by a UV light 614, and the template 610 can be separated fromthe substrate 616 at the z-roller 606 a.

FIG. 6B shows a schematic diagram of another example 650 of using asqueegee roller. A web 652 is drawn along two z-rollers 656 a, 656 b.After the web 652 is locked at the t-roller 656 b, a camera can locatereference marks (or patterns) on a template 660, and a squeegee roller658 can be parked near the locked z-roller 656 b. The non-lockedz-roller 656 a can be raised up out of the way slightly along Zdirection while an adjacent drive roller, that is, the squeegee roller658, can maintain tension and be pulled in some portion of the web 652along X direction as a web path is shortened. In some cases, a z-axisvacuum chuck can be on a substrate 666 to raise the substrate 666 untilthe substrate 666 touches the squeegee roller 658 and the lockedz-roller 656 b. The squeegee roller 658 can move away from the lockedz-roller 656 b while pushing the template 660 into a resist 668 on thesubstrate 666 and forcing out the air. The squeegee roller 658 can stopafter the template 660 is completely in contact with the substrate 666and the resist 668 is cured. After curing, the web 652 and the substrate666 can advance together and the template separation can occur at thez-roller 656 a.

Example Theta Adjustment and Web Angle Measurement

A unique method of correcting for angular misalignment in a theta-zdirection in small amounts is to move one of z-rollers relative to eachother along its axis. FIG. 7A shows a schematic diagram of an example700 of implementing this method. A web 702 can move with z-rollers 706a, 706 b due to high friction, wrap angle, and/or tension. In somecases, an air bearing bushing can be used instead of a roller bearingthat allows for low friction in the rotating and axial directions. Athrusting actuator (not shown) can push on one end of the z-roller shaftand a spring can push on the other end to remove backlash. Thisalignment could cause small waves in the web 702 if the web 702 wasdisplaced too much, however, it might work well enough for small angles.Adjusting the position in this manner can eliminate a need for large,massive, expensive rotational stages either mounted to an x-stage orrotating part or all of the web path and its supporting rollers as asingle unit.

Web angle change is a large component to web alignment error when makinga double-side imprinting. FIG. 7B shows a schematic diagram of anexample method 750 of measuring a web angle for correcting feed-forwardimprinting alignment. The method 750 can directly measure the web angle,e.g., immediately before each imprinting, and the substrate can berepositioned, e.g., by a stage under the substrate chuck, based on themeasured web angle prior to starting the imprinting. For example, asillustrated in FIG. 7B, two non-contact sensors 710 a, 710 b can bepositioned upstream the z-roller 706 b on an edge of the web 702 and beused in conjunction to measure an exact angle of the web 702. Thesensors 710 a, 710 b are stationary and do not move with the web 702.

Examples of Double-Sided Imprinting I. One Step Double Side Imprint;Substrate Nip Feeding

FIG. 8 shows a schematic diagram of an example system 800 of makingdouble-sided imprints on a substrate. The system 800 is configured touse two webs 802 a, 802 b with one above and one below. The web 802 a isdrawn along two z-rollers 804 a and 804 b, and the web 802 b is drawnalong two z-rollers 804 c and 804 d. The webs 802 a, 802 b includerespective templates 806 a, 806 b. The top and bottom templates 806 a,806 b can be located with a vision system, and precision adjustment axiscan be distributed among top and bottom web supports such that the webs802 a, 802 b can be brought into alignment with each other.

In some cases, as FIG. 8 shows, a substrate 810 is coated with resist808 a, and the template 806 b is coated with resist 808 b under thebottom side of the substrate 810 before the template 806 b rolls into animprinting zone, e.g., along X direction. In some cases, the substrate810 can be coated with resist on both top and bottom sides before beingrolled into the imprinting zone. A loading robot can be configured tohold the substrate 810 on edges and feeding the substrate 810 into nipsbetween the rollers 804 b, 804 d as the webs 802 a, 802 b advance whilethe top and bottom z-rollers 804 b, 804 d force the resists 808 a, 808 binto details of the templates 806 a, 806 b and remove air. Once thesubstrate 810 is in complete contact with the templates 806 a, 806 b,the webs 802 a, 802 b and the robot can stop and a UV light can cure theresists 808 a, 808 b. In some implementations, the webs 802 a, 802 b andthe robot are reversed and the templates 806 a, 806 b are separated fromthe substrate 810. In some implementations, the webs 802 a, 802 b areadvanced and pulled away from the rollers 804 a, 804 c to separate fromthe substrate 810. The substrate 810 can be held by another robot on theleft side of the rollers 804 a, 804 c. This process can improveimprinting throughput, although it may not accurately position theimprints.

II. One Step Double Side Imprint with Double Glass Dome

FIG. 9 shows a schematic diagram of another example system 900 offorming imprints on both sides of a substrate 950 at once. The system900 is configured to combine double imprinting method described in FIG.8 with each side imprinting using a separate glass dome as described inFIG. 2. A web 902 is drawn along two z-rollers 906 a and 906 b, and aweb 952 is drawn along two z-rollers 956 a and 956 b. The webs 902, 952include respective templates 920, 970. The system 900 can have thedouble template rolls 920, 970 top and bottom, e.g., separated by a fewmillimeters. The system 900 includes two pressurized glass domes 904 and954 top and bottom, vision alignment systems 912, 962 and precisionadjustment axis (not shown) distributed among the system components fora proper relative alignment of the top and bottom templates 920, 970along Z direction. The system 900 is also configured to dispense resist930 on the top and bottom surfaces of a substrate 950 or on the template920 and/or the template 970 itself

The sequence of imprinting can be as follows: the webs 902 and 952 areadvanced such that a new top template 920 and a new bottom template 970are brought together into an imprinting zone. The vision systems 912 and962 locate reference marks on the templates 920, 970, and the variousadjustment axis align the top and bottom templates 920, 970. The glasspressure domes 904 and 954 are brought into contact with the webs 902,952 on the top and bottom sides. There can be a fine adjustment axis ofthe glass dome 904 or 954 configured to make a small correction foroptimum template alignment after the glass dome 904 Or 954 is in contactwith the web 902 or 952. Resist 930 is applied to the top and bottomsurfaces of the substrate 950. A robot, e.g., with a special low profileend-effector, can present the substrate 950 between the top and bottomtemplates 920, 970 by grabbing the substrate 950 on the edges. The topand bottom glass domes 904 and 954 can come together evenly such that zposition of the substrate 950 is determined by the positions of thepressure domes 904 and 954 as the pressure domes came together. When thedomes 904, 954 are fully flattened and the templates 920, 970 havefilled completely, the resist 930 is cured by a UV lamp 914. Then thepressure domes 904, 954 are retracted from the top and bottom webs 902,952. The webs 902, 952 and the robot can reverse together and thetemplates 920 and 970 are peeled off the substrate 950 at the z-rollers906 a, 956 a.

The technologies described above can address a challenge for double-sideimprinting that is, to successfully embody all of the processrequirements into one tool architecture. The technologies can facilitateUV curing and allow for alignment, even force application, UV resistflow, nano-feature formation, and template and feature separation.

III. Substrate on a Roll

It is desirable to use a suitable low cost substrate material withoptical properties and flexible enough to be wound on a roll, which canallow significant manufacturing cost reductions in high volume. Most ofthe imprinting methods described above might be adaptable to usesubstrates supplied in a roll form, particularly the double glass domeimprinting process as described in FIG. 9. The handling of the substratecan be simpler than an edge gripping method.

FIG. 10 shows a schematic diagram of an example system 1000 that uses alow-cost, flexible substrate 1030 in a roll format with double glassdome imprinting. The double glass dome printing arrangement of thesystem 1000 is similar to the system 900 of FIG. 9. A first web 1002 isdrawn from roller 1008 a along two z-rollers 1006 a and 1006 b to roller1008 b. The web 1002 can be rotated back from roller 1008 b to roller1008 a. The web 1002 includes a first template 1010 that includesimprinting features to be imprinted on a top side of the substrate 1030.A second web 1052 is drawn from roller 1058 a along two z-rollers 1056 aand 1056 b to roller 1058 b. The web 1052 can be rotated back fromroller 1058 b to roller 1058 a. The second web 1052 includes a secondtemplate 1060 that includes imprinting features to be imprinted on abottom side of the substrate 1030. The system 1000 can include twopressurized glass domes 1004 and 1054 top and bottom, vision alignmentsystems 1012, 1062 and a precision adjustment axis (not shown)distributed amongst the system components for a proper relativealignment of the top and bottom templates 1010, 1060 along Z direction.The system 1000 can be configured to dispense resist, e.g., a UV curableresist, on the top and bottom surfaces of the substrate 1030 or on thetemplate 1010 and/or the template 1060 itself

The substrate 1030 is drawn from roller 1032 to roller 1034. In somecases, the substrate 1030 is a blank substrate rolled up on roller 1032,as illustrated in FIG. 10. In some cases, a roll of blank substrate isprotected by a layer of film that is rolled-up together with the blanksubstrate to be the substrate 1030. As the substrate 1030 enters theimprinting region of the system 1000, the protective cover film can beremoved. The templates 1010 and 1060 can be brought into contact withthe substrate 1030 with the pressurized domes 1004 and 1054,respectively. Air can be pushed out of the way until the templates 1010and 1060 are in full contact with the substrate 1030, and a UV light1014 can then cure the resist when the webs 1002, 1052 are stationary.Thus, the blank substrate 1030 becomes a substrate 1040 having bothsides imprinted with corresponding features of the templates 1010 and1060. The domes 1004 and 1054 can be retracted, e.g., by vacuum chucks,from the backs of the templates 1010 and 1060, and separation of thetemplates 1010, 1060 and the substrate 1040 would occur as the webs1002, 1052 are advanced where a path of the substrate 1030 path divergesfrom the paths of the templates 1010, 1060. At this point the imprintedfeatures are fully formed on the substrate 1040.

In some implementations, as FIG. 10 illustrates, the substrate 1040 iswound with a first layer of protection film 1070 on the back side and asecond layer of protection film (not shown) on the front side into asubstrate 1042 rolled onto roller 1034. The first layer of protectionfilm 1070 can be drawn from roller 1072 a through a z-roller 1072 b ontothe back side of the substrate 1040. The second layer of protection filmcan be drawn from another roller (not shown) through another z-roller(not shown) onto the front side of the substrate 1040. A squeegee roller1036, e.g., the squeegee roller 608 of FIG. 6A, can be used to press theprotective films on the substrate 1040. In some cases, another processcan be applied to the imprinted substrate 1040 before winding theprotective films or the substrate 1042 with imprinted features on bothsides can be cut from the roll.

This technology described above allows single-sided patterning ofsubstrates as well as patterning on substrates that have tight frontside-to-back side alignment to be done by keeping them in a roll formatto simplify material handling. By supplying low-cost substrates in aroll format, this technology can be economical to imprint patterns onboth sides of the substrates and keep the substrates in this formatuntil individual parts need to be singulated.

Example Tools for Aligned-Double-Sided Imprints

Nanofabrication equipment typically forms features one side at a time.If a single sided process is used to create features on both sides, itmay essentially take over 2x time and 2x equipment but still have analignment step to align a substrate feature to a template feature.Moreover, the imprinted features after forming are fragile andsusceptible to handling damage. These types of substrates are typicallyhandled with backside contact, but in the case with features on bothsides, touching the backside of the substrate may damage these features.

FIG. 11A shows a schematic diagram of an example tool 1100 foraligned-double-sided imprints on substrates. This tool is configured tofabricate imprinted features on both sides of a substrate whosepositions are tightly controlled with respect to each other. Front sideand back side templates can be pre-aligned to each other opticallybefore imprinting and features on both of the sides can be createdsimultaneously. This tool is also configured to handle the substratewithout damage of the features imprinted on both sides of the substrate.

In some implementations, the imprinting tool 1100 includes three zones:(a) substrate input; (b) imprint engine; and (c) imprinted substrateoutput. Two webs 1102 a, 1102 b are drawn through z-rollers 1104 a, 1104c to z-rollers 1104 b, 1104 d, respectively. The webs 1102 a, 1102 bhave respective flexible templates, e.g., CRTs, that are drawn togetherin a region where a substrate 1112 is inserted. The substrate 1112 canbe a wafer substrate and taken out from a substrate container 1110storing a number of blank substrates. A robot 1106 is configured to takevia a robot holder 1108 the substrate 1112 from the container 1110 andinsert into the region between the flexible templates.

Before the substrate 1112 is inserted, reference marks on the templatesof each web 1102 a, 1102 b can be optically aligned to one another witha camera system and actuation that allows relative positioning of thewebs 1102 a, 1102 b. As discussed with further details below, the tool1100 of FIG. 11A can include a clamping system for clamping the two webs1102 a and 1102 b. After the reference marks are aligned, the webs 1102a, 1102 b can be clamped to each other to eliminate relative motion ofthe templates. The webs 1102 a, 1102 b can be reversed to allow for theinsertion of the substrate 1112, and UV curable resist from resistinjection heads 1114 a, 1114 b can be applied to the templates and thenthe templates can be brought back together in alignment with thesubstrate and resist between them. As the substrate 1112 travels througha process zone in zone (b), a UV light source 1116 can cure the resist.After the curing, the clamping system can be unclamped to separate thewebs 1102 a, 1102 b to allow the imprinted substrate 1118 pass through,as illustrated in FIG. 12H below. The fully imprinted substrate 1118from the substrate 1112 can then exit and be taken by another robotholder 1120 of another robot 1122 and stored into an imprinted substratecontainer 1124. The imprinted substrates 1118 in the container 1124 canbe stored in soft cushions and separated from each other.

FIG. 11B shows a schematic diagram of an example tool 1150 foraligned-double-sided imprints on substrates. Compared to the tool 1100of FIG. 11A, the tool 1150 does not include the unloading automationhaving the robot 1122 and the container 1124 in zone (c). Instead, theimprinted substrate 1118 can be reversed back to zone (a) and stored inthe container 1110. In this way, the tool 1150 can eliminate theunloading automation for the imprinted substrate 1118 and combine theunloading automation with the substrate loading automation. Similar tothe tool 1100, the tool 1150 can also include a clamping system having avacuum chuck 1208 for the web 1102 a and a clamp 1210 for the web 1102b. After the reference marks on the web 1102 a are aligned with thereference marks on the web 1102 b, the webs 1102 a, 1102 b can beclamped together by the clamping system to each other to eliminaterelative motion of the templates.

In an example processing sequence, the substrate 1112 is lowered into atop between the two templates on the webs 1102 a and 1102 b fordouble-side imprinting. After the imprinting is completed and fullycured with the UV light source 1116, the z-rollers 1104 a and 1104 c canbe reversely rotated, such that the fully imprinted substrate 1118 isretrieved from the top by the same robot handler 1108 and the robot1106. In this way, the vacuum chuck 1208 and the clamp 1210 do not needto be unclamped to allow the imprinted substrate 1118 exit from thebottom and can keep the templates aligned. Thus, the configuration ofthe tool 1150 (and the processing sequence) can allow the templatealignment to be maintained for each sequential substrate, which canyield a significant decrease in process time because the time consumingalignment process is only done once on each set of templates.

FIG. 12A-1 to FIG. 12I show schematic diagrams of example operationalprocedures of the imprinting tool 1100 of FIG. 11A. For illustrationonly, the operation procedures show the concept where the substratestravel in a vertical direction from top to bottom. Other configurations,e.g., the tool being inverted so that the substrates can travel frombottom to top or even horizontally, can also be implemented. It is alsonoted that one or more operational procedures shown in FIG. 12A-1 toFIG. 12I can be also used for the imprinting tool 1150 of FIG. 11B.

FIGS. 12A-1 to 12A-5 show alignment of reference marks 1204 a, 1204 b,1204 c, 1204 d on templates 1214 a, 1214 b of the webs 1102 a, 1102 b.The imprinting tool 1100 can includes a clamping system, including avacuum chuck 1208 for the web 1102 a and a clamp 1210 for the web 1102b. The vacuum chuck 1208 can be the vacuum chuck 308 or 310 of FIG. 3A.The vacuum chuck 1208 is positioned on linear guides 1207 along a linearaxis (or rail) 1206. The imprinting tool 1100 can also include a pair ofnip rollers 1212 a, 1212 b that are retractable and can be moved out ofthe way of the webs 1102 a, 1102 b during imprinting. As discussed inFIG. 13F with further details, the nip rollers 1212 a, 1212 b can bemoved close to each other to facilitate unloading the imprintedsubstrate 1118.

FIG. 12A-3 shows an example template 1214 a on the web 1102 a. Thetemplate 1214 a includes multiple features 1215 arranged within an area.In a particular example, the substrate 1112 to be imprinted is a wafer,and the area can have a shape and a size similar to those of the wafer.For example, the area can have a diameter D, e.g., about 200 mm. Thetemplate 1214 a has two reference marks (or alignment marks) 1204 a,1204 b, which are designed to be aligned with leading and trailing edgesof the substrate 1112 during imprinting. Similarly, the template 1214 bon the web 1102 b also has two reference marks 1204 c, 1204 d, which arealso designed to be aligned with the leading and trailing edges of thesubstrate 1112 during imprinting. Accordingly, the reference mark 1204 aneeds to match with the reference mark 1204 c, and the reference mark1204 b needs to match with the reference mark 1204 d, so that featureson the templates 1214 a, 1214 b can be aligned with the substrate 1112and imprinted to double sides of the substrate 1112.

A first alignment camera 1202 a can be used to align the reference marks1204 a, 1204 c on a first end of the templates 1214 a, 1214 b. A secondalignment camera 1202 b can be used to align the reference marks 1204 b,1204 d on a second end of the templates 1214 a, 1214 b. An upper diagramof FIG. 12A-4 shows misalignments between the templates 1214 a, 1214 b,where the reference marks 1204 a and 1204 c do not match with each otherand the reference marks 1204 b and 1204 d do not match with each other.The templates 1214 a, 1214 b can be adjusted in x, y, and/or thetadirections until the reference marks on the templates 1214 a, 1214 boverlap with each other, e.g., 1204 a with 1204 c, 1204 b with 1204 d,as the lower diagram of FIG. 12A-4 shows. In some cases, the thetaadjustment for the templates 1214 b, 1214 b can be implemented byadjusting at least one of the z-rollers relative to each other along itsaxis, as illustrated in FIG. 7. In some cases, the vacuum chuck 1208first chucks on the web 1102 a and adjusts the position of the web 1102a in x, y, and/or theta directions. FIG. 12A-2 shows a bottom view ofFIG. 12A-1 before adjustment, while FIG. 12A-5 shows a bottom view ofFIG. 12A-1 with theta adjustment, where the clamp 1210 is also rotatedand the linear guides 1207 move along the linear axis 1206 up on one endof the clamp 1210 and down on the other end of the clamp 1210.

The templates 1214 a, 1214 b, e.g., CRTs, can be adjusted in X, Y, thetadirections. As illustrated in FIG. 12A-4, X direction shows the CRTadvance direction, and Y direction is across the width of the CRT. Thecamera system, 1202 a & 1202 b can see or view the CRT references marks1204 a, 1204 b, 1204 c, 1204 d and use the reference marks as feedbackfor relative positioning. The relative position of the webs 1102 a, 1102b in the X direction, can be controlled by advancing one of the webs onone side relative to the other of the webs with the web drive rollers,or can be moved through the vacuum chuck 1208 with the linear guides oractuators 1207. The air turn bars 1104 a-1104 d allow the webs to slidein the X, Y, theta directions with minimal fiction, thus allowing anaccurate relative correction to place the reference marks in alignment.The roller assemblies 1300, as illustrated in FIG. 13A, can move in theY direction to provide the relative motion. Also, a linear actuator 1207can be placed into the vacuum chuck 1208 to control the webs in the Ydirection. The theta-direction adjustment can be accomplished by adifferential motion of the linear actuators 1207 that communicate themotion through the vacuum chuck 1208.

After the reference marks 1204 a, 1204 b on the web 1102 a are alignedwith the reference marks 1204 c, 1204 d on the web 1102 b, the webs 1102a, 1102 b can be clamped by the clamping system, e.g., the vacuum chuck1208 and the clamp 1210, to each other to eliminate relative motion ofthe templates 1214 a, 1214 b. The clamping system can be positioneddownstream of the leading reference marks 1204 a, 1204 c. FIGS. 12B-1 to12B-3 show schematic diagrams of configurations for clamping the webs1102 a, 1102 b.

FIG. 12B-3 is a section view of FIG. 12B-2, which shows a clampingconfiguration. The vacuum chuck 1208 is supported by a pair of clampingactuators (and guides) 1218 for counter balance, which are furthersupported by a clamp bar 1210 with a rubber pad 1222 on top. The linearguides 1207 are connected to the vacuum chuck 1208 on one end viaconnectors 1209 and connected on the other end to the linear rail 1206that is further connected to a machine frame 1220. The clampingconfiguration is configured such that the clamped webs 1102 a, 1102 bcannot have relative motion at or near the clamp 1210. Differentialforces can be minimized or eliminated, such that the templates 1214 a,1214 b (e.g., CRTs) can have a good alignment in a region large enoughto encompass the substrate. The vertical linear rail 1206 is configuredto pull and guide the templates 1214 a, 1214 b along a precise path at aconstant velocity.

FIGS. 12C-12D show schematic diagrams of an example of dispensing UVresist 1224 onto the templates 1214 a, 1214 b. The webs 1102 a, 1120 bare moved upwards reversely to expose the templates 1214 a, 1214 b tothe resist injection heads 1114 a, 1114 b. The clamping system includingthe vacuum chuck 1208 and the clamp 1210 is moved together with the webs1102 a, 1102 b. When the reference marks 1204 c, 1204 d reversely passthe resist injection heads 1114 a, 1114 b, the resist injection heads1114 a, 1114 b can start to dispense the UV resist 1224 onto thetemplates 1214 a, 1214 b. When the reference marks 1204 a, 1204 b arrivethe resist injection heads 1114 a, 1114 b, the dispense of UV resist1224 on the templates 1214 a, 1214 b completes and the reverse movementalso completes. During the movement, tensions are matched in bothtemplates 1214 a, 1214 b.

After the dispense of UV resist 1224 completes, the webs 1102 a, 1120 bare advanced downwards. At a certain point, as shown in FIG. 12E, asubstrate 1112 is inserted into a gap between the templates 1214 a, 1214b. The gap is closed when the substrate 1112 and the UV resist 1224 areall moved downwards between the webs 1102 a, 1102 b, as illustrated inFIG. 12F. The clamping system is also moved download together with theclamped webs 1102 a, 1102 b.

As the substrate 1112 and the templates 1214 a, 1214 b with the UVresist 1224 travel through the process zone (b), as shown in FIG. 12G,the UV source 1116 cures the UV resist 1224 onto the substrate 1112 tobecome a fully imprinted substrate 1118 with features on both sides. Asillustrated in FIG. 12H, the fully imprinted substrate 1118 is pulleddown to exit the process zone (b), and the vacuum chuck 1208 and theclamp 1210 are unclamped to separate the webs 1102 a, 1102 b. Theimprinted substrate 1118 is then moved out and can be taken by the robotholder 1120 of the robot 1122 and stored into the imprinted substratecontainer 1124.

Then the tool 1100 can be reset for imprinting a next substrate 1112, asillustrated in FIG. 12I. The reset step can include separating the niprollers 1212 a, 1212 b, retracing the linear guides 1207, tension of thewebs 1102 a, 1102 b, advancing the webs 1102 a, 1102 b, findingreference marks on the templates 1214 a, 1214 b, spreading air-turns,transferring the imprinted substrate 1118 (e.g., into the container1124), and preparing a blank substrate 1112.

This imprinting tool 1100 adopts a vertical configuration, where theresist injection heads can dispense the UV resist in a symmetric andhorizontal orientation. It also provides symmetric forces gravity,spreading and separation, and particle isolation imprinting chamber, andallows feeding of ultra-thin substrates easier and more reliable.

FIGS. 13A-13F show schematic diagrams of example feature configurationsof the tool 1100 of FIGS. 11A to 12I for double-sided imprinting. It isalso noted that one or more feature configurations shown in FIG. 13A toFIG. 13E can be also used for the imprinting tool 1150 of FIG. 11B.

FIG. 13A shows a schematic diagram of an example configuration 1300 forweb path. The web 1102 a can be supplied from a supply roller 1302 a andadvanced via driver rollers 1304 a, 1306 a, the z-rollers 1104 a, 1104b, and driver rollers 1308 a, 1310 a, to roller 1312 a in a clockwisedirection, while the rollers 1306 a and 1308 a rotate in acounter-clockwise direction. In some cases, the web 1102 a from thesupply roller 1302 a includes protection film. The driver roller 1304 acan rotate in the clockwise direction and the roller 1306 a can rotatein the counter-clockwise direction to take off the protection film fromthe web 1102 a so that the template 1214 a on the web 1102 a is exposed.Similarly, the web 1102 b can be supplied from a supply roller 1302 band advanced via driver rollers 1304 b, 1306 b, the z-rollers 1104 c,1104 d, and driver rollers 1308 b, 1310 b, to roller 1312 b in acounter-clockwise direction, while the rollers 1306 b and 1308 b rotatein a clockwise direction. In some cases, the web 1102 b from the supplyroller 1302 b includes protection film. The driver roller 1304 b canrotate in the counter-clockwise direction and the roller 1306 b canrotate in the clockwise direction to take off the protection film fromthe web 1102 b so that the template 1214 b on the web 1102 b is exposed.In some cases, the driver roller 1306 b is a separate nip roller anddriven by a driver roller 1306 b′.

In some implementations, the configuration 1300 includes tension sensors1314 a, 1314 b coupled to the z-roller 1104 b, 1104 d and configured tomeasure the tensions of the webs 1102 a, 1102 b, respectively.

In some implementations, the z-rollers 1104 a, 1104 b, 1104 c, 1104 dare rollers with low friction. In some implementations, the z-rollers1104 a, 1104 b, 1104 c, 1104 d are air-turn rollers. As illustrated inFIG. 13B, the air-turn roller 1104 a can float the web 1102 a via air1315 and does not put lateral or angular constraint on the web 1104 a.In some examples, the air-turn roller 1104 a includes a central shaft1320 and a cover 1318 made of porous material that is supported by thecentral shaft 1320. There is an empty space between the central shaft1320 and the cover 1318. Air pressure 1315 can be pressed onto the spacethrough an inlet 1316 and escapes from the cover 1318 to support thecover 1318, such that a plenum of air 1315 is created between anoriginal position of the cover 1318 and a current position of the cover1318. The air-turn roller provides several advantages: 1) if a typicalz-roller is used, a small amount of misalignment or theta correction cancause lateral stresses and displace the top-to-bottom pattern alignment;2) there is low risk of particle transfer between the z-roller and theweb; 3) because of template floatation around air turn, large particlesmay affect less imprint area; 4) a skewed web may not track straightover a roller; and 5) the air turn may not resist the motion of thelinear axis 1206. FIG. 13C shows an implementation of FIG. 12A-5 withthe z-rollers 1104 a, 1104 b being air-turn rollers.

FIG. 13D shows a schematic diagram of an example configuration 1330 forimprinting process. The tool 1100 includes a chamber 1332 configured toisolate the imprint engine process zone, e.g., zone (b) of FIG. 11A,from external environment. The chamber 1332 can be controlled to have aconstant temperature, e.g., 25° C., and/or a level of cleanness forimprinting.

FIG. 13E shows a schematic diagram of an example substrate loadingconfiguration 1350. The web 1102 a can be pulled back, e.g., movedreversely, by rotating the rollers 1302 a, 1304 a, 1306 a, 1104 a, 1104b in a counter-clockwise direction to wrap onto the roller 1306 a.Similarly, the web 1102 b can be pulled back, e.g., moved reversely, byrotating rollers 1302 b, 1304 b, 1306 b and the rollers 1104 c, 1104 din a clockwise direction to wrap onto the roller 1306 b. The robot 1106is configured to take via the robot holder 1108 a blank substrate 1112from the container 1110 and insert into the region between the flexibletemplates. The substrate 1112 can be a wafer substrate, and thecontainer 1110 can be a wafer container 1110′.

FIG. 13F shows a schematic diagram of an example substrate unloadingconfiguration 1370. By rotating rollers 1104 b, 1308 a, 1310 a, 1312 a,the web 1102 a can be pulled downwards, e.g., advanced, in a clockwisedirection to wrap onto the roller 1312 a. Similarly, the web 1102 b canbe pulled downwards, e.g., advanced, in a counter-clockwise direction towrap onto roller 1312 b by rotating the rollers 1104 d, 1308 b, 1310 b,1312 b. When the webs 1102 a, 1102 b are pulled downwards, the clampingsystem releases and the webs 1102 a, 1102 b are separated. After thefully imprinted substrate 1118 passes a position of the nip rollers 1212a, 1212 b, the nip rollers 1212 a, 1212 b can be close to each other tohold tightly the webs 1102 a, 1102 b. The fully imprinted substrate 1118can then exit and be taken by the robot holder 1120 of the robot 1122and stored into an imprinted substrate container 1124. The substrate1112 can be a wafer substrate, and the container 1124 can be a wafercontainer 1124′ for storing double-sided imprinted substrates 1118.

Note that substrates of different shapes and sizes can be imprintedthrough this double sided process equipment, besides the roundsubstrates indicated in the figures. Higher part throughput can beachieved when larger substrates are run that can be cut up into morepieces. Also, the width of the CRT is flexible and a wider web canimprint larger substrates, leading to higher part throughput.

Example Scheme for Simultaneous Double-Sided Imprints

FIG. 14 shows a schematic diagram of another example tool 1400 fordouble-sided imprinting on a substrate, e.g., a wafer substrate. Forillustration only, the substrate travels in a horizontal direction fromright to left. Other configurations, e.g., the tool being inverted sothat the substrates can travel from left to right or even vertically,can also be implemented.

A bottom web 1402 a is drawn along two z-rollers 1404 a, 1404 b. The web1402 a includes a template 1406 a, e.g., CRT. The template 1406 a caninclude grating features, as illustrated in FIG. 14. The template 1406 ais configured to have pre-pattered through holes such that a vacuumchuck 1416 under the template 1406 a can gently hold with vacuum asubstrate 1414, e.g., a wafer, when the substrate 1414 is released by atop load Equipment Front End Module (EFEM) 1408 a. The vacuum chuck 1416can be movable together with the template 1406 a. The top load EFEM 1408a can be positioned between a pair of dispenser head 1410 a, 1410 b, sothat the first dispenser head 1410 a can dispense resist on the gratingfeatures of the template 1406 a before the substrate 1414 is placed onthe template 1406 a and the second dispenser head 1410 b can dispenseresist on the substrate 1414 after the substrate 1414 is held on thetemplate 1406 a by the vacuum chuck 1416.

Another top web 1402 b is drawn along two z-rollers 1404 c, 1404 d. Theweb 1402 b includes a template 1406 b (e.g., CRT) that can includefeatures, e.g., grating features or other features. A UV light source1412 can be positioned above the template 1406 b. The second dispenserhead 1410 b can be arranged before the z-roller 1404 c so that, when thesubstrate 1414 is moved under the template 1406 b, the second dispenserhead 1410 b already dispenses the resist on top of the substrate 1414.The tool 1400 also includes another top load EFEM 1408 b positionedadjacent to the z-roller 1404 b. As discussed in further details below,the top load EFEM 1408 b is configured to take the substrate 1414 withimprints from the template 1406 a.

FIGS. 15A to 15H show schematic diagrams of example procedures of usingthe tool of FIG. 14 for double-sided imprinting.

FIG. 15A shows a schematic diagram of dispensing resist 1504 a on thebottom template 1406 a. The first dispenser head 1410 a can start todispense the resist 1504 a after an alignment mark 1502 a passed thefirst dispenser head 1410 a, so that the resist 1504 a is dropped ontofeatures of the template 1406 a after the alignment mark 1502 a, e.g.,right to the alignment mark 1502 a. After a certain amount of resist1504 a is dropped onto the features of the template 1406 a, the web 1402a can stop moving and wait for a period of time until the resist 1504 aspreads, as shown in FIG. 15B, on the features of the template 1406 a.In some examples, the template 1406 a includes a grating featureconfigured to enable the resist drop spread nicely, e.g., uniformly, topush air out of the way, such that the resist 1504 a fills in detailswithin the template 1406 a. A grating period of the grating features canbe tens of nanometer (nm) to tens of micrometer (μm).

After the resist 1504 a spreads on the features of the template 1406 a,the web 1402 a can be moved again. When the resist 1504 a movesunderneath the top load EFEM 1408 a, the web 1402 a can stop, and thesubstrate 1414 can be loaded by the top load EFEM 1408 a onto the resist1504 a and held by the vacuum chuck 1416, as shown in FIG. 15C. Thus, abottom surface of the substrate 1414 contacts with the resist 1504 a.

Then the web 1402 a can be moved again. When the substrate 1414 arrivesunder the second dispenser head 1410 b, the second dispenser head 1410 bstarts to dispense resist 1504 b onto a top surface of the substrate1414, as shown in FIG. 15D. In some cases, the web 1402 a can stop towait until the resist 1504 b spreads on the top surface of the substrate1414. In some cases, the web 1402 a continues to be moved while theresist 1504 b spreads on the top surface of the substrate 1414. The tool1400 can be configured such that a distance between the second dispensehead 1410 b and the z-roller 1404 c is long enough for the resist 1540 bto spread nicely on the top surface of the substrate 1414.

When the substrate 1414 with the resist 1504 a on the bottom surface andthe resist 1504 b on the top surface is moved under the template 1406 b,features on the template 1406 b starts to contact the resist 1504 b andthe resist 1504 b fills in the features on the template 1406 b. Alsowhen the alignment mark 1502 a is moved to be aligned with anotheralignment mark 1502 b on the template 1406 b, e.g., via a camera system,the top web 1402 b can start to be moved at a rate same as the bottomweb 1402 a, Also a distance between the top template 1406 b and thebottom template 1406 a can be configured or controlled to enable theresist 1504 b fills into the features of the template 1406 a but thefeatures do not contact with the top surface of the substrate 1414. FIG.15E shows a schematic diagram of the substrate 1414 with double sideimprinting, e.g., the top resist 1504 b in contact with the top template1406 b and the bottom resist 1504 a in contact with the bottom template1406 a.

When the substrate 1414 with the top resist 1504 b and the bottom resist1504 a and the templates 1406 b and 1406 a are moved under the UV lightsource 1412, the UV light source 1412 can be turned on to cure theresists 1504 a and 1504 b, so that features on the templates 1406 a and1406 b can be imprinted onto resists on the top and bottom surfaces ofthe substrate 1414. The substrate 1414 with imprinted resists is notedas an imprinted substrate 1414′.

After the resists 1504 a, 1504 b are cured onto the substrate 1414, thetop web 1402 b is pulled upwards around the z-roller 1404 d so that thetemplate 1406 b is separated from the imprinted substrate 1414′, asillustrated in FIG. 15F. To achieve this, the z-roller 1404 b can bepositioned with a distance from the z-roller 1404 d.

The web 1402 a is further moved until under the top load EFEM 1408 b.The vacuum chuck 1416 can release the substrate 1414′, and the top loadEFEM 1408 b can take the imprinted substrate 1414′, as shown in FIG.15G. The top load EFEM 1408 b holding the imprinted substrate 1414′ canmove forward, e.g., to the left of the z-roller 1404 b, so that theimprinted substrate 1414′ is separated from the bottom template 1406 a,as illustrated in FIG. 15H.

Using the tool 1400 for double-sided imprinting as described above canprovide several advantages. First, no substrate registration is needed.Second, alignment is implemented with a top template to a bottomtemplate to eliminate imprint related difficulty. Third, the bottomtemplate can have pre-patterned through holes to enable gentle vacuumhold of the substrate and to guarantee the substrate being held duringseparation from the top template. Fourth, the tool can enable gentleseparation scheme with low separation force, which can avoid highseparation force to cause substrate lost or separation failure at bothtop and bottom imprints. Fifth, the bottom template has grating featureswhich are configured to allow resist spread on the bottom template toeliminate filling concern of bottom imprints.

Example Double-Sided Imprinting Processes

FIG. 16 is a flow diagram of an example process 1600 of fabricatingdouble-sided imprints on a substrate. The process 1600 can be performedby the devices, systems and/or tools describe above, e.g., theimprinting tool 1100 of FIGS. 11-13F.

A first web is drawn along first rollers and a second web is drawn alongsecond rollers (1602). The first web includes a first template thatincludes a first imprinting feature, e.g., a grating feature. The secondweb includes a second template that includes a second imprintingfeature, e.g., a grating feature.

In some implementations, the first rollers include two first z-rollersarranged in a vertical direction, and the second rollers include twosecond z-rollers arranged in the vertical direction. The first z-rollerscan be positioned opposite to the second z-rollers with a distance. Thefirst web can be drawn along the first z-rollers in a counter-clockwisedirection, and the second web can be drawn along the second z-rollers ina clockwise direction.

In some examples, the first rollers include at least one air turn rollerconfigured to float the first web by air pressure. The air turn rollercan be the roller 1104 a of FIGS. 13A-13B. The second rollers can alsoinclude at least one air turn roller configured to float the second webby air pressure. In some examples. the first rollers include at leastone air turn roller configured to chuck the first web by vacuum, e.g.,the air bearing turn bar 354 of FIG. 3B.

Reference marks on the first web and the second web are aligned (1604).A camera system (e.g., the alignment cameras 1202 a, 1202 b of FIG.12A-1) or a laser system (e.g., the laser 504 and the sensor 508 of FIG.5A) can be used to locate (or detect) the reference marks on the firstweb and the second web for alignment. An alignment system can be used toalign the reference marks on the first web and the second web, such thatthe first template and the second template are aligned with each other,for example, the first imprinting feature is aligned with the secondimprinting feature.

In some examples, aligning the reference marks on the first web and thesecond web includes aligning a first reference mark on the first webwith a second reference mark on the second web and aligning a thirdreference mark on the first web with a fourth reference mark on thesecond web. The first reference mark and the third reference mark candefine a range where the substrate is configured to be imprinted withthe first template. The second reference mark and the fourth referencemark can define a range where the substrate is configured to beimprinted with the second template.

In some implementations, aligning the reference marks on the first weband the second web includes moving a z-roller of the first rollers in atleast one of x, y, or theta direction, as discussed above in FIGS. 12A-1to 12A-5.

In some implementations, after the aligning, the first web and thesecond web are clamped at a location adjacent to the reference marks,such that the clamped first web and second web are moved with the firsttemplate and the second template aligned with each other. For example,as illustrated in FIG. 12B-1, the clamping location is downstream thefirst reference mark.

The first web and the second web can be clamped together by a clampingsystem. The clamping system can include a chuck and a clamp. The chuckcan be a vacuum chuck, e.g., the vacuum chuck 1208 of FIG. 12A-1 andconfigured to chuck onto the first web with vacuum. The clamp can be theclamp 1210 of FIG. 12A-1. The chuck can be actuated to chuck with theclamp so that the chuck is onto the first web and the clamp is onto thesecond web.

In some cases, the chuck is configured to be movable along a railparallel to an axis defined by the first rollers, and the chuck and theclamp are moved together with the first web and the second web after theclamping. As illustrated in FIG. 12B-3, the chuck can be positioned on apair of guides, and each of the guides is movable on a respective railconnected to a frame. Aligning the reference marks on the first web andthe second web can include adjusting relative positions of the guides onthe respective rails in at least one of x, y, or theta direction. Atension sensor can be coupled to one of the first rollers to measuretension of the first web. Another tension sensor can be coupled to oneof the second rollers to measure tension of the second web.

In some implementations, a chamber is used to enclose at least the firsttemplate and the second template. The clamber can be the chamber 1332 ofFIG. 13D. A controller can be configured to control a temperature and/orcleanness of the chamber.

The first web is drawn along the first rollers in a first direction toexpose the first template to a first dispenser and the second web isdrawn along the second rollers in a second direction to expose thesecond template to a second dispenser (1606). The first template can bedrawn to be in a horizontal direction and under the first dispenser. Thesecond template can be drawn to be in a horizontal direction and underthe second dispenser.

The first dispenser dispenses first resist on the first template and thesecond dispenser dispenses second resist on the second template (1608).The first dispenser can dispense the first resist while the firsttemplate is passing the first dispenser. The second dispenser candispense the second resist while the second template is passing thesecond dispenser.

When the first template is fully covered with the first resist and thesecond template is fully covered with the second resist, the first weband the second web are reversely drawn (1610), such that the firsttemplate with the first resist and the second template with the secondresist face to each other. For example, the first web can be drawnupwards in a counter-clockwise direction to expose the first templatefor resist, and the first web can then be drawn downwards in a clockwisedirection to pull the first template down. Similarly, the second web canbe drawn upwards in a clockwise direction to expose the second templatefor resist, and the second web can then be drawn downwards in acounter-clockwise direction to pull the second template down.

A substrate is inserted between the first template with the first resistand the second template with the second resist (1612). The substrate canbe a rigid substrate, e.g., a wafer substrate like a silicon wafer. Arobot can be controlled to grip an edge of the substrate to feed thesubstrate into a gap between the first template and the second template.In some implementations, the first rollers and the second rollers arearranged such that, after the inserting, the substrate is moved togetherwith the first template and the second template, and the first resist ispressed, e.g., by one of the first rollers, onto the first side of thesubstrate and filled into the first imprinting feature on the firsttemplate and the second resist is pressed, e.g., by one of the secondrollers, onto the second side of the substrate and filled into thesecond imprinting feature on the second template.

In some implementations, a first squeegee roller is moved onto the firstweb to push the first template into the first resist, such that thefirst resist fills into the first imprinting feature on the firsttemplate, and a second squeegee roller is moved onto the second web topush the second template into the second resist, such that the secondresist fills into the second imprinting feature on the second template.The first squeegee roller and the second squeegee roller can bepositioned opposite to each other during moving together the firstsqueegee and the second squeegee. The first squeegee roller or thesecond squeegee roller can be the squeegee roller 608 of FIG. 6A.

When the substrate and the first template, the second template enterinto an imprinting zone, a light source, e.g., a UV light source, canilluminate to cure the first resist and the second resist (1614), suchthat the cured first resist has a first imprinted feature correspondingto the first imprinting feature on the first template on a first side ofthe substrate and the cured second resist has a second imprinted featurecorresponding to the second imprinting feature on the second template ona second side of the substrate. In such a way, the substrate isimprinted with double-sided imprinted features.

In some implementations, after the curing, the first web and the secondweb are unclamped, such that the substrate with the cured first resistand second resist is capable of passing through a gap between the firstweb and the second web.

The double-imprinted substrate is unloaded (1616). The substrate can beunloaded by another robot and stored in a container, e.g., the container1124 of FIG. 11A.

FIG. 17 is a flow diagram of another example process 1700 of fabricatingdouble-sided imprints on a substrate. The process 1700 can be performedby the devices, systems, and/or tools described above, e.g., theimprinting tool 1400 of FIGS. 14 to 15H.

A first web is drawn along first rollers (1702). The first web includesa first template that has a first imprinting feature, e.g., a gratingfeature. The first rollers can include two z-rollers arranged in ahorizontal direction and can be drawn from right to left. In someimplementations, the first rollers include at least one air turn rollerconfigured to float the first web by air pressure. The first rollers caninclude at least one air turn roller configured to chuck the first webby vacuum.

First resist is dispensed on the first template (1704). A firstdispenser can start to dispense the first resist on the first templatewhen a beginning of the first template is moved under the firstdispenser and end when an end of the first template leaves the firstdispenser. After the first resist is dispensed on the first template,the tool can wait for a period of time until the first resist spreadsinto the first imprinting feature of the first template. In someimplementations, the first imprinting feature includes a gratingfeature, and the grating feature is configured such that the firstresist uniformly fills into the grating feature. Other imprintingfeatures can be also used and configured to spread the first resistuniformly.

A substrate is loaded onto the first template (1706). A first side ofthe substrate, e.g., a bottom side, is in contact with the first resiston the first template. Particularly, the first side of the substrate isloaded opposite to the first imprinting feature of the first template.The substrate can be a rigid substrate, e.g., a silicon wafer. A holder,e.g., the top load EFEM 1408 a of FIG. 14, can be used to hold andrelease the substrate onto the first template. The holder can bearranged next to the first dispenser along the moving direction of thefirst web.

The substrate is clamped onto the first template (1708), such that thesubstrate is movable together with the first template. A chuck, e.g.,the vacuum chuck 1416 of FIG. 14, can be used to chuck the substrateonto the first template. In some implementations, the first templateincludes one or more pre-pattered through holes, and the substrate canbe held with vacuum by the vacuum chuck through the one or morepre-patterned through holes. The vacuum chuck is movable and can bemoved together with the first web and the substrate after the clamping.

Second resist is dispensed on a second side of the substrate (1710),e.g., a top side of the substrate. A second dispenser can be arrangednext to the holder and start to dispense the second resist on thesubstrate when the substrate is moved under the second dispenser.

A second web is drawn along second rollers. The second web includes asecond template that has a second imprinting feature to be imprintedonto the substrate. The second rollers can include two second z-rollersarranged in the horizontal direction. As illustrated in FIG. 14, the twofirst z-rollers define a first moving range for the first web and thetwo second z-rollers define a second moving range for the second web.The first moving range is larger than the second moving range andencloses the second moving range. The first rollers and the secondrollers can be arranged to define a gap between the first web and thesecond web. The gap has a vertical distance.

Reference marks on the first web and the second web are aligned (1712).As illustrated in FIG. 15D, a first reference mark on the first web canbe arranged ahead of the first imprinting feature along a direction ofdrawing the first web, e.g., left to a position where the substrate isclamped. A second reference mark on the second web can be also arrangedahead of the second imprinting feature along the direction, e.g., leftto a position where the second imprinting feature is to be imprintedonto the second side of the substrate.

For the alignment, the second web can be static and wait for the firstreference mark on the first web to move close to the second referencemark. A vision system can be used to locate the second reference markand/or the first reference mark. When the first reference mark is movedto match with the second reference mark, the first template is alignedwith the second template, e.g., the first imprinting feature is alignedwith the second imprinting feature.

After the alignment, the first web and the second web are drawnsimultaneously (1714) at a same rate. In some implementations, thesecond reference mark is arranged adjacent to one of the secondz-roller. When the first reference mark on the first web is moved tomatch with the second reference mark, the second web starts to be drawnalong the second z-rollers, and the second template starts to bepressed, e.g., by the one of the second z-rollers, into the secondresist on the second side of the substrate. The vertical distance of thegap between the first web and the second web can be configured so thatthe second template is pressed into the second resist and the secondresist fills into the second imprinting feature of the second template.

In some implementations, the vertical distance of the gap is high sothat the second resist is not contact with the second template when thesubstrate is moved into the gap. When the first reference mark on thefirst web and the second reference mark on the second web are aligned,the second z-rollers together with the second web can be movedvertically downwards so that the second template is pressed into thesecond resist on the second side of the substrate.

In some implementations, a squeegee roller, e.g., the squeegee roller608 of FIG. 6A, is moved on the second web between the two secondz-rollers to push the second template into the second resist, such thatthe second resist fills into the second imprinting feature. In somecases, the first resist can be also pressed into the first imprintingfeature by the squeegee roller.

The first resist and the second resist are cured (1716). A light source,e.g., a UV light source, can be positioned between the two secondz-rollers and cure the first resist and the second resist when thesubstrate is between the first template and the second template and thefirst resist and the second resist are both pressed into the firstimprinting feature and the second imprinting feature, respectively.Thus, the cured first resist can have a first imprinted featurecorresponding to the first imprinting feature on the first side of thesubstrate and the cured second resist can have a second imprintedfeature corresponding to the second imprinting feature on the secondside of the substrate.

The double-sided imprinted substrate is unloaded (1718). In someimplementations, after the curing, the second web is drawn and pulledupwards along one of the second z-rollers to separate from thesubstrate, then a holder, e.g., the top load EFEM 1408 b of FIG. 14, isused to take the substrate while the vacuum chuck under the firsttemplate is releasing the substrate.

FIG. 18 is a flow diagram of a third example process 1800 of fabricatingdouble-sided imprints on a substrate. The process 1800 can be performedby the devices, systems, and/or tools described above, e.g., theimprinting tool 900 of FIG. 9 or the imprinting tool 1000 of FIG. 10.

A first web is drawn along first rollers and a second web is drawn alongsecond rollers (1802). The first web includes a first template that hasa first imprinting feature to be imprinted on one side of the substrate,and the second web includes a second template that has a secondimprinting feature to be imprinted on the other side of the substrate.The first template and the second template are brought together into animprinting zone.

Reference marks for the first template and the second template arealigned (1804). A camera system or a laser system can be used to detectthe reference marks on the first web and the second web for alignment ofthe first template and the second template. For example, by aligning afirst reference mark on the first web with a second reference mark onthe second web, the first imprinting feature on the first template canbe aligned with the second imprinting feature on the second template.

First resist is dispensed on a first side of the substrate and secondresist is dispersed on a second side of the substrate (1806). The firstresist and the second resist can be held on the sides of the substrateby surface tension.

The substrate is fed into the imprinting zone and between the firsttemplate and the second template (1808). In some cases, the substrate isrigid, e.g., a silicon wafer, and the substrate can be provided bygripping an edge of the substrate using a holder. In some cases, asillustrated in FIG. 10, the substrate is flexible, and the substrate canbe provided by pulling from a roll of blank substrates along a roller.

In some implementations, the first rollers include two first z-rollersarranged in a horizontal direction and the second rollers include twosecond z-rollers arranged in the horizontal direction. The first rollersand/or the second rollers can be moved vertically to increase ordecrease a vertical distance between the first web and the second web.

The first template and the second template are pressed onto thesubstrate (1810), such that the first resist fills into the firstimprinting feature of the first template on the first side of thesubstrate and the second resist fills into the second imprinting featureof the second template on the second side of the substrate.

In some implementations, a first press dome is applied to the firsttemplate, e.g., from the back of the first template. The first pressdome can be a glass dome, e.g., the glass dome 204 of FIG. 2 or 454 ofFIG. 4B. The first press dome can be an annular ring vacuum chuck, e.g.,the vacuum chuck 104 of FIG. 1. In some implementations, the second webis supported by a planar support, e.g., the stage 130 of FIG. 1, or thestage assembly 230 of FIG. 2. In some implementations, a second presshome is applied to the second template, e.g., from the back of thesecond web. The second press dome can be a glass dome, e.g., the glassdome 204 of FIG. 2 or 454 of FIG. 4B. The second press dome can be anannular ring vacuum chuck, e.g., the vacuum chuck 104 of FIG. 1.

In some implementations, after the alignment of reference marks, thefirst press dome and the second press dome are brought into contact withthe first web and the second web. There can be a fine adjustment axis ofthe first press dome or the second press dome configured to make a smallcorrection for optimum template alignment after the first press dome orthe second press dome is in contact with the first web or the secondweb. The first and second press domes can come together evenly such thatz position of the substrate is determined by the positions of the firstand second press domes as the first and second press domes cametogether. When the first and second press domes are fully flattened, thefirst and second templates can be filled with the first resist and thesecond resist completely.

In some implementations, pressing the first template and the secondtemplate onto the substrate includes moving a first squeegee roller ontothe first web to push the first template into the first resist, suchthat the first resist fills into the first imprinting feature on thefirst template, and/or moving a second squeegee roller onto the secondweb to push the second template into the second resist, such that thesecond resist fills into the second imprinting feature on the secondtemplate. The first squeegee roller and the second squeegee roller canbe positioned opposite to each other during moving the first squeegeeand the second squeegee together.

The first resist and the second resist are cured (1812), e.g., by a UVlight source. The cured first resist can have a first imprinted featurecorresponding to the first imprinting feature on the first side of thesubstrate, and the cured second resist can have a second imprintedfeature corresponding to the second imprinting feature on the secondside of the substrate.

The double-sided imprinted substrate is unloaded (1814). For example,the first web can be pulled away from one of the first rollers toseparate the first template from the substrate. The second web can bepulled away from one of the second rollers to separate the secondtemplate from the substrate. In some implementations, the first pressdome and/or the second press dome is first retracted from the first weband/or the second web.

In some implementations, after the substrate is separated from the firsttemplate, a first protective film is applied onto the cured first resiston the first side of the substrate. After the substrate is separatedfrom the second template, a second protective film can be applied ontothe cured second resist on the second side of the substrate. Thedouble-sided imprinted substrate, particularly with the first and/orsecond protective films, can be rolled into a roll over a roller.

FIG. 19 is a flow diagram of a fourth example process 1900 offabricating double-sided imprints on a substrate. The process 1900 canbe performed by the devices, systems, and/or tools described above,e.g., the imprinting tool 800 of FIG. 8.

A first web is drawn along a first roller and a second roller (1902).The first web includes a first template having a first imprintingfeature. The first roller and the second roller can be positioned in afirst direction, e.g., a horizontal direction or a vertical direction.

A second web is drawn along a third roller and a fourth roller (1904).The second web includes a second template having a second imprintingfeature. The third roller and the fourth roller can be positioned in asecond direction same as the first direction, e.g., a horizontaldirection or a vertical direction. The first roller and the third rollerare positioned opposite to each other and define a nip. Note that step1902 and step 1904 can be executed at the same time.

Reference marks for the first template and the second template arealigned (1906), such that the first template is aligned with the secondtemplate. As noted above, a camera system or a laser system can be usedto locate the reference marks on the first web and the second web forthe alignment. Additionally, an alignment system can be used to alignthe reference marks for the first template and the second template. Forexample, precision adjustment axis can be distributed among web supportsfor the first web and the second web such that the first template andthe second template can be brought into alignment with each other.

First resist is dispersed on a first side of the substrate or the firsttemplate and second resist is dispensed on a second side of thesubstrate or the second template (1908). In some cases, the first resistand the second resist can be dispersed on both sides of the substrate.In some cases, the first resist is deposited on the first side of thesubstrate, and the second resist is deposited on the second template, asillustrated in FIG. 8.

The first template and the second template are simultaneously drawn intothe nip and the substrate is fed into the nip at the same time (1910).The first imprinting feature faces the first side of the substrate andthe second imprinting feature faces the second side of the substrate,and the first resist can be pressed by the first roller into the firstimprinting feature on the first side of the substrate and the secondresist can be pressed by the third roller into the second imprintingfeature on the second side of the substrate. The substrate can be fedinto the nip by using a holder griping an edge of the substrate. Thesubstrate can be a rigid substrate, e.g., a wafer.

Once the substrate is in complete contact with the first template andthe second template, the first web, the second web, and the substratecan stop moving. The first resist and the second resist are cured(1912), e.g., by a UV light, such that the cured first resist has afirst imprinted feature corresponding to the first imprinting feature onthe first side of the substrate and the cured second resist has a secondimprinted feature corresponding to the second imprinting feature on thesecond side of the substrate.

The double-sided imprinted substrate is unloaded (1914). In someimplementations, step 1914 can be similar to step 1814 of FIG. 18. Thefirst web can be pulled away from the second roller and the second webcan be pulled away from the fourth roller, such that the substrate isseparated from the first template and the second template. The substratecan be gripped by another holder. In some implementations, the first webis reversely drawn to be pulled away from the first roller and thesecond web is reversely drawn to be pulled away from the third roller.The substrate is retracted back by the same holder for feeding. In sucha way, the substrate can be separated from the first template and thesecond template.

A number of implementations have been described. Nevertheless, it willbe understood that various modifications may be made without departingfrom the spirit and scope of the techniques and devices describedherein. Features shown in each of the implementations may be usedindependently or in combination with one another. Additional featuresand variations may be included in the implementations as well.Accordingly, other implementations are within the scope of the followingclaims.

What is claimed is:
 1. (canceled)
 2. A system for double-sidedimprinting, comprising: first rollers for moving a first web including afirst template; second rollers for moving a second web including asecond template; an alignment system configured to align reference markson the first web and the second web such that the first template and thesecond template are aligned with each other; a first dispenserconfigured to dispense a first resist on the first template; a seconddispenser configured to dispense a second resist on the second template;a loading system configured to insert a substrate between the firsttemplate and the second template; and a light source configured to curethe first resist and the second resist, such that the cured first resisthas a first imprinted feature associated with the first template on afirst side of the substrate and the cured second resist has a secondimprinted feature associated with the second template on a second sideof the substrate, wherein, in operation, the first web is drawn alongthe first rollers in a first direction to expose the first template tothe first dispenser and the second web is drawn along the second rollersin a second direction to expose the second template to the seconddispenser, and then, the first web is drawn along the first rollers in adirection opposite the first direction and the second web is drawn alongthe second rollers in a direction opposite the second direction, suchthat the first template with the first resist and the second templatewith the second resist are aligned with each other.
 3. The system ofclaim 2, further comprising: an unloading system configured to unloadthe substrate with the first imprinted feature on the first side and thesecond imprinted feature on the second side.
 4. The system of claim 2,further comprising a clamping system configured to: clamp the first weband the second web at a location adjacent to the reference marks, suchthat the clamped first web and second web are moved with the firsttemplate and the second template aligned with each other; and unclampthe first web and the second web, such that the substrate with the curedfirst resist and second resist is capable of passing through a gapbetween the first web and the second web.
 5. The system of claim 4,wherein the clamping system comprises: a chuck configured to chuck thefirst web; and a clamp configured to clamp the second web when actuatedwith the chuck.
 6. The system of claim 5, wherein the chuck comprises avacuum chuck configured to chuck onto the first web with vacuum.
 7. Thesystem of claim 5, wherein the chuck is movable, and wherein the chuckand the clamp are moved together with the first web and the second webafter the clamping.
 8. The system of claim 5, wherein the chuck ispositioned on a pair of guides, and each guide of the pair of guides ismovable on a respective rail connected to a frame, and wherein thealignment system is configured to align the reference marks on the firstweb and the second web by adjusting a relative position of the guides onthe respective rails in at least one of x, y, or theta direction.
 9. Thesystem of claim 2, wherein the first rollers and the second rollers arearranged such that, after the substrate is inserted between the firsttemplate and the second template, the substrate is moved together withthe first template and the second template, and the first resist ispressed onto the first side of the substrate and filled into a firstimprinting feature on the first template and the second resist ispressed onto the second side of the substrate and filled into a secondimprinting feature on the second template, and wherein the firstimprinted feature on the first side of the substrate corresponds to thefirst imprinting feature on the first template, and the second imprintedfeature on the second side of the substrate corresponds to the secondimprinting feature on the second template.
 10. The system of claim 2,wherein the alignment system is configured to align the reference markson the first web and the second web by moving a z-roller of the firstrollers in at least one of x, y, or theta direction.
 11. The system ofclaim 2, further comprising a locating system configured to locate thereference marks on the first web and the second web for alignment,wherein the locating system comprises at least one of a camera system ora laser system.
 12. The system of claim 2, wherein the first rollerscomprise at least one air turn roller configured to float the first webby air pressure.
 13. The system of claim 2, wherein the first rollerscomprise at least one air turn roller configured to chuck the first webwith vacuum.
 14. The system of claim 2, wherein the first direction is acounter-clockwise direction with respect to the first rollers, and thesecond direction is a clockwise direction with respect to the secondrollers.
 15. The system of claim 2, wherein the first rollers comprisetwo first z-rollers arranged in a vertical direction, and the secondrollers comprise two second z-rollers arranged in the verticaldirection, and wherein the first dispenser is configured to dispense thefirst resist on the first template when the first template is in ahorizontal direction relative to the two first z-rollers, and the seconddispenser is configured to dispense the second resist on the secondtemplate when the second template is in the horizontal direction. 16.The system of claim 2, further comprising first and second tensionsensors configured to measure tensions of the first web and the secondweb, respectively.
 17. The system of claim 2, further comprising: achamber configured to enclose the first template and the secondtemplate; and a controller configured to control at least one oftemperature or cleanness of the chamber.
 18. The system of claim 2,further comprising a detecting system arranged before one of the firstrollers, the detecting system comprising at least a camera system or alaser system, wherein the detecting system is configured to locate afirst one of the reference marks on the first web.
 19. The system ofclaim 2, further comprising: a first squeegee roller arranged on thefirst web and configured to be moved to push the first template into thefirst resist, such that the first resist fills a first imprintingfeature on the first template; and a second squeegee roller arranged onthe second web and configured to be moved to push the second templateinto the second resist, such that the second resist fills a secondimprinting feature on the second template.
 20. A system for double-sidedimprinting, comprising: first rollers for moving a first web including afirst template having a first imprinting feature; second rollers formoving a second web including a second template having a secondimprinting feature; a first dispenser configured to dispense a firstresist on the first template; a loading system configured to load asubstrate onto the first template, such that a first side of thesubstrate is in contact with the first resist on the first template; aclamping system configured to clamp the substrate onto the first web,such that the substrate is movable together with the first web; a seconddispenser configured to dispense a second resist on a second side of thesubstrate; a locating system configured to locate a first reference markon the first web with a second reference mark on the second web foraligning the first reference mark with the second reference mark; alight source configured to cure the first resist and the second resist,such that the cured first resist has a first imprinted featurecorresponding to the first imprinting feature on the first side of thesubstrate and the cured second resist has a second imprinted featurecorresponding to the second imprinting feature on the second side of thesubstrate; and an unloading system configured to unload the substratewith the first imprinted feature on the first side and the secondimprinted feature on the second side, wherein, after the first referencemark and the second reference mark are aligned with each other, thefirst web and the second web are drawn simultaneously at a same rate.21. A system for double-sided imprinting, comprising: first rollersconfigured to move a first web including a first template having a firstimprinting feature; second rollers configured to move a second webincluding a second template having a second imprinting feature; one ormore dispensers configured to dispense a resist; a locating systemconfigured to locate reference marks on the first web and the second webfor aligning the first template and the second template; a light sourceconfigured to cure the resist, such that a first portion of the curedresist has a first imprinted feature corresponding to the firstimprinting feature on a first side of a substrate, and a second portionof the cured resist has a second imprinted feature corresponding to thesecond imprinting feature on a second side of the substrate; and amoving system configured to feed the substrate between the firsttemplate and the second template and unload the substrate with the firstimprinted feature on the first side and the second imprinted feature onthe second side.